Fix postfix deref eval/interpreter regressions and JVM ->%[]

[fglock]

Summary

Fixes several postfix dereference regressions.

• JVM: implement correct index/value slice semantics for ->%[...] (returns alternating index/value pairs).
• Eval-string interpreter: allow glob lvalue assignment where the LHS is an expression (*EXPR = ..., e.g. "mysubalias"->** = ...) by compiling the glob expression and emitting STORE_GLOB.
• Runtime: fix PVIO postfix glob deref (->** on *STDOUT{IO}) by creating a temporary glob when the scalar holds a RuntimeIO (handles both GLOB and GLOBREFERENCE representations), preventing ClassCastException.
• Interpreter disassembly: keep disassembly in sync for DEREF_HASH and guard string pool lookups.
• Parser/compiler: add/compile postfix key/value slices (->%{...} / ->%[...]) and interpreter opcode for hash key/value slices.

Repro

• JVM ->%[...]:
  • perl5_t/t/op/postfixderef.t line 317
• Eval-string interpreter path:
  • JPERL_EVAL_USE_INTERPRETER=1 perl5_t/t/op/postfixderef.t

Notes

This PR is a checkpoint; remaining eval-string interpreter differences are still being worked on (e.g. tests 70-71, 36, and postderef_qq interpolation cases under JPERL_EVAL_USE_INTERPRETER=1).