[Feature Request] Allow specific builds to run integ tests in parallel

[Swiddis]

Is your feature request related to a problem? Please describe

I've been working on updating our plugin's integration tests to manage distinct resources so that our integration suites can run in parallel, but I haven't been able to actually persuade the integTest plugin to let us parallelize suites. This might be related to the hardcoded getMaxParallelForks value, but when I set this to another value locally I still didn't see integTest running suites in parallel. I also found a reference to this tests.jvms property but this also had no effect.

Describe the solution you'd like

Provide a way to enable integTest suite parallelization on a per-project level. (Or at least point me to the correct place to update)

Related component

Build

Describe alternatives you've considered

No response

Additional context

No response

[Swiddis]

Though the scope of this issue is just to make this a global flag, even nicer would be to support Junit-style suite annotations, which we could use to incrementally mark suites as safe to run in parallel with others. This would allow attacking major timewasters without needing to migrate an entire project. It'd internally depend on a RwLock or equivalent.