WIP: DESTROY support for blessed objects

[fglock]

Summary

Add DESTROY support for blessed objects. When a blessed reference is discarded, its DESTROY method is called if one exists in the class hierarchy.

Triggers

• undef $obj - explicitly discards a blessed reference
• delete $hash{key} - removes a blessed reference from a hash
• Loop scope exit - existing scopeExitCleanup path now also fires DESTROY

Implementation

• RuntimeBase.java: Added destroyCalled boolean flag to prevent double-DESTROY
• RuntimeScalar.java: Added callDestroyIfNeeded() static method that finds DESTROY via InheritanceResolver.findMethodInHierarchy(), calls it in void context, and catches exceptions as "(in cleanup)" warnings
• RuntimeHash.java: Calls callDestroyIfNeeded() on values removed by delete()
• EmitStatement.java: Updated comments to reflect DESTROY in scope-exit cleanup

Limitations

Without reference counting, DESTROY may fire early if other references to the object still exist. The destroyCalled flag prevents double-DESTROY but does not solve the fundamental problem.

Scope-exit DESTROY is currently limited to loop bodies only. Extending it to all scopes (subroutines, eval blocks, if/else) requires reference counting to avoid destroying objects that are still referenced elsewhere. This was tested and caused 20+ unit test failures.

Future work

Targeted reference counting on blessed objects would allow safe scope-exit DESTROY for all contexts. Key points:

• Add refCount field to RuntimeBase, increment on copy/bless, decrement on overwrite/scope-exit
• Only call DESTROY when refCount reaches 0
• Zero impact on hot path (reference types always go through setLarge())

Test plan

• make passes
• Reference counting implementation (future)
• Scope-exit DESTROY for all contexts (future)

Generated with Devin