fix(Scalar-List-Utils): bump bundled modules to v1.70; fix pair*, uniq, get-magic

[fglock]

Summary

Running ./jcpan -t Scalar::Util (which tests the CPAN Scalar-List-Utils-1.70 distribution against the bundled PerlOnJava implementation) went from:

• 25/38 test programs failing, 209/832 subtests failing

to:

• 21/38 test programs failing, 163/842 subtests failing

−46 subtest failures, 4 whole test programs now pass: t/00version.t, t/getmagic-once.t, t/pair.t, t/undefined-block.t.

What changed

Version sync to 1.70

• Bumped List::Util, Scalar::Util, Sub::Util from the 1.63 stubs to v1.70 (both the .pm files and the $VERSION strings exposed by the Java implementations).
• List::Util.pm now defines:
  • an import that touches caller's $a/$b (RT #88848, silences spurious "Name used only once" warnings);
  • the List::Util::_Pair class with key / value / TO_JSON methods.

ListUtil.java

• Validate code-ref arguments for reduce / reductions / first / any / all / none / notall and the pair* family:
  • non-CODE args now croak Not a subroutine reference;
  • calls into undefined stubs croak Undefined subroutine in <func>.
• pairmap / pairgrep / pairfirst now alias $a and $b in the caller's package to the source list elements (matches Perl 5 XS semantics), so modifications inside the block propagate to the caller.
• pairgrep / pairmap warn on odd-sized input lists (Odd number of elements in pairmap/pairgrep).
• pairs() blesses returned arrayrefs into List::Util::_Pair so ->key, ->value, ->TO_JSON work.
• unpairs() pads short input arrayrefs with undef.
• uniq distinguishes undef from the empty string; uniq / uniqstr / uniqint / uniqnum now warn on undef with the proper uninitialized-value warning.
• head / tail croak Not enough arguments for List::Util::head|tail on empty argument lists.

ScalarUtil.java

• blessed / reftype / refaddr now trigger FETCH on tied scalars exactly once before inspecting the underlying value (fixes t/getmagic-once.t).

Remaining work (not in this PR)

Most of the remaining 163 subtest failures are concentrated in:

• t/exotic_names.t (120 failures): stash / sub names containing NUL, control characters, or apostrophes. Needs deeper work in set_subname + caller() to preserve embedded NULs in package/sub names.
• t/subname.t (7): related to the above.
• BigInt integration in sum / product / min (3+3+1): large integers drop to floats because the operators use double arithmetic.
• Misc edge cases: overload support in blessed / uniqint / uniqnum, tied filehandle recognition in openhandle, DESTROY tracking in sample / shuffle / uniqstr, taint propagation, weakref edge cases.

Test plan

• make passes locally (unit tests all green).
• ./jcpan -t Scalar::Util now reports Failed 21/38 test programs. 163/842 subtests failed, down from 25/38 / 209/832.
• CI green.

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