runtests: assume Time::HiRes, drop Perl Win32 dependency

[vszakats]

Time::HiRes was already used unconditionally before this patch in
servers.pm. This package, and functions used by runtests (sleep and
gettimeofday) are supported by the minimum Perl version required for
curl:

https://perldoc.perl.org/5.8.0/Time::HiRes

• Drop the portable_sleep() wrapper in favor of Time::HiRes::sleep().
• Use Time::HiRes unconditionally in serverhelp.pm.
• Stop using the Win32 package where available. It was included
  to provide a Windows fallback for Time::HiRes::sleep(). It was never
  actually called (on supported Perl versions), but the dependency may
  have loaded Win32.dll, which often appears in failed fork operations
  in GHA logs.
  Ref: a6fed41 Improvements for the Perl-based testsuite running on Windows #5054 Various attempts to improve AppVeyor Windows builds #5034
  Ref: Windows CI/GHA, jobs failing #14854

---

Most likely doesn't make a difference in practice.

[vszakats]

And indeed the fork error remains, but it's now happening not with Win32.dll, but
some other components, this time without a name:

  === End of file commands.log
        0 [main] sh 8300 dofork: child -1 - forked process 13096 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
        0 [main] sh 8302 dofork: child -1 - forked process 12976 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
        0 [main] sh 8304 dofork: child -1 - forked process 2800 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
        0 [main] sh 8305 dofork: child -1 - forked process 13112 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
        0 [main] sh 8308 dofork: child -1 - forked process 11900 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  1011832 [main] sh 8300 dofork: child -1 - forked process 10456 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  1003261 [main] sh 8302 dofork: child -1 - forked process 8424 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
        0 [main] sh 8314 dofork: child -1 - forked process 13244 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
        0 [main] sh 8315 dofork: child -1 - forked process 10868 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  1004164 [main] sh 8304 dofork: child -1 - forked process 11892 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
   998926 [main] sh 8305 dofork: child -1 - forked process 9436 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  sh: fork: retry: Resource temporarily unavailable
  1009453 [main] sh 8308 dofork: child -1 - forked process 4808 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  1003113 [main] sh 8314 dofork: child -1 - forked process 9608 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
   999918 [main] sh 8315 dofork: child -1 - forked process 12792 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  3013327 [main] sh 8300 dofork: child -1 - forked process 13080 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  3007128 [main] sh 8302 dofork: child -1 - forked process 7556 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  3008969 [main] sh 8304 dofork: child -1 - forked process 6224 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  3004024 [main] sh 8305 dofork: child -1 - forked process 6440 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  sh: fork: retry: Resource temporarily unavailable
  3012533 [main] sh 8308 dofork: child -1 - forked process 8608 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
        0 [main] sh 8328 dofork: child -1 - forked process 11656 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  3002441 [main] sh 8314 dofork: child -1 - forked process 4868 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  2999999 [main] sh 8315 dofork: child -1 - forked process 11620 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
   997773 [main] sh 8328 dofork: child -1 - forked process 12264 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  7016623 [main] sh 8300 dofork: child -1 - forked process 9176 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  7010141 [main] sh 8302 dofork: child -1 - forked process 12304 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  2998462 [main] sh 8328 dofork: child -1 - forked process 13308 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  7027697 [main] sh 8304 dofork: child -1 - forked process 8272 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  7022492 [main] sh 8305 dofork: child -1 - forked process 11148 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  sh: fork: retry: Resource temporarily unavailable
  7015011 [main] sh 8308 dofork: child -1 - forked process 10992 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  7005512 [main] sh 8314 dofork: child -1 - forked process 12556 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable
  7003605 [main] sh 8315 dofork: child -1 - forked process 11268 died unexpectedly, retry 0, exit code 0xC0000142, errno 11
  sh: fork: retry: Resource temporarily unavailable

https://github.com/curl/curl/actions/runs/16971072810/job/48107907170?pr=18290