8362968: [JVMCI] support modifying locals in StackIntrospection on virtual threads

[tkrodriguez]

This a draft of adding support for JVMTI deferred locals on virtual threads. The JDK issue has a more full description but basically I'd like some feedback on whether the strategy seems ok and whether full JVMTI support for deferred locals would be a desired outcome. If it's not then I might be able to recast this in a way that is more JVMCI specific so it requires fewer changes to the core JVMTI deferred locals support which is probably the scariest looking part. Maybe @AlanBateman and @kevinjwalls could offer some opinions here?

For the deopt/loom interactions I tried to make the use of the chunk for heap frames fairly explicit as the absolutized heap frames make me nervous. But maybe I'm just making it too complicated?

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Issue

• JDK-8362968: [JVMCI] support modifying locals in StackIntrospection on virtual threads (Enhancement - P3)

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[sspitsyn]

@tkrodriguez Thank you for working on this! I'll look at the JVMTI and related changes but it is going to take some time.