[ASDAlexander77]

Follow-up to #619. That PR left three cases leaking. This handles them:

Case	Before (rc / own)	After
Temporary before a statement that holds a yield (const n = ("b"+i).length; if (n > 0) { yield n; }), 500000 runs	165 MB / 165 MB	4.4 / 4.4 MB
Yielded value yield "a" + i	50.5 MB / 4.4 MB	4.4 / 4.4 MB
Yielded object yield new C(i)	50.5 MB / 4.4 MB	4.4 / 4.4 MB
own/own_generator.ts	11.2 MB (spec table) / 4.4 MB	4.4 / 4.4 MB
Temporary used after a yield	cannot occur: MLIRGen keeps locals that cross a yield in the state object	—

Changes (all in OwnedReturnConsumptionPass unless noted)

• Release point: releaseRangeEnd now stops at the first op that is a yield or resume point, or that has one inside it. The release goes in front of that op.
• rc, yielded record: retainYieldedRecords retains the {value, done} record before each ts.YieldReturnVal, the way a return statement does (§9.24). The record then owns its fields, and a fresh value made for it is an ordinary temporary released before the yield. Under own the value still moves into the record, and the store rule (escapesThroughStore) stays for every model except rc.
• rc, classification: functionReturnsOwned classifies a generator's next like any function, with yields counted as returns.
• rc, caller: calleeNameOf resolves next read out of a field of the state object that only ever holds it. The map is own_facts::FieldFunctions, moved out of OwnershipSignaturePass (own's behavior is unchanged), so the caller takes the record over.

Side effect worth a look

Under rc, a module with a generator (including any .map/.filter, which MLIRGen builds as generators) used to count as having an unclassified owning return. That kept the whole-module rule (closedWorld) off for it. Now it can be on, so calls through plain values in those modules take over their results, following the +1 convention. The full suite agrees.

Tests

• 00generator_temporaries.ts gains items (yield new Item), next() called by hand and kept past the next call, and a declared C function, so the whole-module rule can't stand in for the field resolution.
• generator-temporaries.cmake checks:
  • the record retain and both releases before each yield;
  • the releases before the if in branchYield;
  • that every next call in main whose record holds a heap value takes it over. This fails when the field resolution is turned off (checked).
  • that under own strings still keeps the concatenation and passes the verifier.
• The check fails on the old compiler.
• Full ctest -C Release -j 16: 4767/4767 pass.

Not done: no DefaultLib rc rebuild with this compiler. Nothing about how calls cross a library boundary changes: the caller's takeover needs the state object's constant in its own module, which an imported generator never has, so such a call leaks as before rather than being freed early.

Separate bug found: ("a" + i) + (yield 1) crashes the compiler in every model (proposed as its own task).

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