fix: fix IO::Util test failures - select() with tied handles, syswrite, and more

[fglock]

Summary

Fix 6 bugs causing IO::Util CPAN module test failures. Results improved from 5/9 test files failing to only 1/9 (the remaining test_pod.t fails due to POD encoding, not our code).

Bugs Fixed

• select() returns wrong value for tied handles: select() was returning "TIED_HANDLE(test_tie)" instead of "main::STDOUT" when STDOUT was tied. This broke IO::Util::capture which relies on select() to get the current handle name and uses *{$name} to tie/untie it. Fixed by propagating globName from the previous IO handle to the TieHandle, and updating TieHandle.toString() to return globName when available.

• qr/./=> token splitting: Lexer greedily tokenized /= from qr/./=> as divide-assign. After regex parser consumed /, the remaining = wasn't merged with next > to form => fat comma. Added merge logic in StringParser.java.

• 1-argument open not implemented: open HANDLE (1-arg form) was throwing PerlJavaUnimplementedException. Implemented by reading filename from $_.

• syswrite on tied handles: TieHandle check was after ClosedIOHandle check; since TieHandle's ioHandle is always ClosedIOHandle, tied handles were caught early and returned undef. Moved TieHandle check before closed-handle check.

• gethostbyname aliases field flattening: Empty RuntimeArray for aliases field was flattening to zero elements in list context, shifting subsequent fields. Changed to empty string scalar in all 8 network functions.

• sprintf zero-pad flag for missing args: %03d with missing argument produced " 0" instead of "000". Added check for 0 flag to choose pad character.

Files Changed

• TieOperators.java - propagate globName to TieHandle
• TieHandle.java - use globName in toString()
• StringParser.java - qr//=> token merge
• IOOperator.java - 1-arg open, syswrite tie order
• ExtendedNativeUtils.java - network aliases flattening
• SprintfOperator.java - sprintf zero-pad
• RuntimeScalar.java - globDeref RuntimeIO lookup

Test plan

• make passes (all unit tests)
• IO::Util 01_capture.t passes 10/10 tests (was 7/10)
• IO::Util full suite: 8/9 files pass, 99/100 tests pass
• tie_handle.t unit test passes

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