RFR: 8371369: Parallel: Relax precondition of PSOldGen::expand_and_allocate

[Francesco Andreuzzi]

On Wed, 5 Nov 2025 19:29:13 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Use more precise precondition for heap/old-gen expansion; the same precondition is also used in its sole caller.
> 
> Test: tie1-5

Marked as reviewed by fandreuzzi (Author).

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PR Review: https://git.openjdk.org/jdk/pull/28162#pullrequestreview-3425155624