RFR: 8319161: GC: Make TestParallelGCThreads use createTestJavaProcessBuilder [v2]

[duke]

On Tue, 2 Dec 2025 08:56:28 GMT, Ramkumar Sunderbabu <rsunderbabu at openjdk.org> wrote:

>> Summary of change:
>> 
>> 1. executeLimitedTestJava changed to executeTestJava to allow flags to be propagated to forked processes.
>> 2. `@requires vm.gc == null` - this line is added to skip runs that use GC flags in test vm options. Allowing GC flags will result in VM initialization error ("Multiple garbage collectors selected").
>> 3. Addition of ZGC to list of parallel collectors
>> 
>> Testing:
>> HS Tiers 1 and 2
>> Ran with all flag combinations in CI
>
> Ramkumar Sunderbabu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   separating test sections

@rsunderbabu 
Your change (at version e10d268d1780b1baa6c3a0ae6fef6b3effad42eb) is now ready to be sponsored by a Committer.

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PR Comment: https://git.openjdk.org/jdk/pull/28566#issuecomment-3601558681