fix(given/when): implicit break and skip smartmatch on boolean exprs

[fglock]

Summary

Fix two bugs in PerlOnJava's given/when transformation that caused DateTime::Calendar::Discordian to fail 21/73 subtests in t/cardinals.t under jcpan -t (e.g. 1st came out as 1stth).

The failing test pattern:

given ($i) {
    when ($i % 10 == 1 && $i != 11) { $cardinal .= 'st' }
    when ($i % 10 == 2 && $i != 12) { $cardinal .= 'nd' }
    when ($i % 10 == 3 && $i != 13) { $cardinal .= 'rd' }
    default                          { $cardinal .= 'th' }
}

Bug 1 — missing implicit last

Per perlsyn, after a when block runs, control implicitly breaks out of the enclosing given. PerlOnJava just expanded when (COND) { BLOCK } into if ($_ ~~ COND) { BLOCK }, so every when (and the default) ran in turn, producing things like 1stth.

Fix: append a synthetic last; to every parsed when-block and mark the synthesized given BlockNode as isLoop = true so that last exits the given instead of escaping to an outer loop / the program.

Bug 2 — when always smart-matched against $_

Per perlsyn, when(EXPR) does not smart-match against $_ when EXPR is one of:

• a comparison: ==, !=, <, >, <=, >=, <=>, eq, ne, lt, gt, le, ge, cmp
• a boolean combinator: &&, ||, //, and, or, xor
• a regex bind: =~, !~
• a negation: !, not
• defined / exists

PerlOnJava unconditionally wrapped, so e.g. when ($i % 10 == 2 && $i != 12) for $i = 2 became 2 ~~ 1 (false) instead of using the boolean 1 directly.

Fix: add whenIsBoolean(...) to detect those exceptional forms and use the expression's value directly as a boolean instead of wrapping with $_ ~~.

Test plan

• jcpan -t DateTime::Calendar::Discordian — Files=16, Tests=271 ... Result: PASS (was 21/73 failures in t/cardinals.t)
• make — full unit-test suite green, no regressions
• Spot checks confirming when semantics match perl for both smart-match and boolean cases

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