Keep stash CODE globs callable after each/list assignment #1963

Summary

Copying CODE globs out of a package stash with each %stash and a list assignment can leave the copied CV non-callable on PerlOnJava. DDC::Any::mapstash uses this pattern while exporting the pure-Perl DDC::PP backend.

Reproducer

package Example::PP;
our @Names = qw(First Second);
our %Values = (First => 1, Second => 2);
for my $name (@Names) {
    no strict 'refs';
    *{$name} = sub { $Values{$name} };
}
package main;
my $source = \%{'Example::PP::'};
my $destination = \%{'Example::Any::'};
while (my ($name, $glob) = each %$source) {
    $destination->{$name} = $glob;
}
print Example::Any::First();

System Perl prints 1; PerlOnJava returns undef. Looking up each value directly with keys %$source works, which narrows the issue to the stash-entry path through each and list assignment.

CPAN evidence

• Distribution: DDC::Concordance 0.50, pure Perl; optional DDC::XS tests were skipped.
• CPAN random-tester run: 20261103-123832-91742; record DDC::Any from DDC::Concordance.
• System Perl: all 471 suite tests pass.
• PerlOnJava JVM and interpreter: 62/452 subtests fail in t/10b_any_import_pp.t, t/11_any_constants.t, t/12_any_compiler.t, t/14_any_qcount.t, and t/15_any_qfilter.t.
• Prerequisites NetServer::Generic 1.03 and Parse::Yapp were installed in the archived run; no native library, service, or platform prerequisite explains the failure.

Environment: macOS arm64, Java 24.0.2. The project regression will cover both PerlOnJava backends.