RFR: 8304303: implement VirtualThread class notifyJvmti methods as C2 intrinsics [v4]

[Serguei Spitsyn]

> This is needed for performance improvements in support of virtual threads.
> The update includes the following:
> 
> 1. Refactored the `VirtualThread` native methods:
>     `notifyJvmtiMountBegin`     and `notifyJvmtiMountEnd`      => `notifyJvmtiMount`
>     `notifyJvmtiUnmountBegin` and `notifyJvmtiUnmountEnd` => `notifyJvmtiUnmount`
> 2. Still useful implementation of old native methods is moved from `jvm.cpp` to `jvmtiThreadState.cpp`:
>      `JVM_VirtualThreadMountStart`       => `VTMS_mount_begin`
>      `JVM_VirtualThreadMountEnd`         => `VTMS_mount_end`
>      `JVM_VirtualThreadUnmountStart`  = > `VTMS_unmount_begin`
>      `JVM_VirtualThreadUnmountEnd`    => `VTMS_mount_end`
> 3. Intrinsified the `VirtualThread` native methods: `notifyJvmtiMount`, `notifyJvmtiUnmount`, `notifyJvmtiHideFrames`.
> 4. Removed the`VirtualThread` static boolean state variable `notifyJvmtiEvents` and its support in `javaClasses`.
> 5. Added static boolean state variable `_VTMS_notify_jvmti_events` to the jvmtiVTMSTransitionDisabler class as a replacement of the `VirtualThread` `notifyJvmtiEvents` variable.
> 
> Implementing the same methods as C1 intrinsics can be needed in the future but is a low priority for now.  
> 
> Testing:
>  - Ran mach5 tiers 1-6. No regressions were found.

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

  minor tweaks in intrisics implementation

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13054/files
  - new: https://git.openjdk.org/jdk/pull/13054/files/f3692263..8233f0ab

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13054&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13054&range=02-03

  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/13054.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/13054/head:pull/13054

PR: https://git.openjdk.org/jdk/pull/13054