RFR: 6960970: Debugger very slow during stepping [v6]

[Serguei Spitsyn]

> This change fixes a long standing performance issue related to the debugger single stepping that is using JVMTI `FramePop` events as a part of step over handling. The performance issue is that the target thread continues its execution in very slow `interp-only` mode in a context of frame marked for `FramePop` notification with the JVMTI `NotifyFramePop`. It includes other method calls recursively upon a return from the frame.
> 
> This fix is to avoid enforcing the `interp-only` execution mode for threads when `FramePop` events are enabled with the JVMTI `SetEventNotificationMode()`. Instead, the target frame has been deoptimized and kept interpreted by disabling `OSR` optimization by the function `InterpreterRuntime::frequency_counter_overflow_inner()`. (Big thanks to @fisk for this suggestion!) Additionally, some tweaks are applied in several places where the `java_thread->is_interp_only_mode()` is checked.
> The other details will be provided in the first PR request comment.
> 
> Testing:
>  - test `serviceability/jvmti/vthread/ThreadStateTest` was updated to provide some extra test coverage
>  - submitted mach5 tiers 1-6

Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:

  review: optimize hide_single_stepping and post_method_exit

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28407/files
  - new: https://git.openjdk.org/jdk/pull/28407/files/d82e4efe..bb4b11f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28407&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28407&range=04-05

  Stats: 14 lines in 1 file changed: 5 ins; 3 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/28407.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28407/head:pull/28407

PR: https://git.openjdk.org/jdk/pull/28407