RFR: 8286957: Held monitor count

[Robbin Ehn]

The current implementation do not count all monitor enter, counts high up in abstraction and causes a performance regression on aarch64 with some benchmarks due to C2 changes.

This change makes the counting exact by pushing the counting down in the abstraction.
The additional JNI counter is strictly not needed, but enables us to figure out if we have monitors "on stack".

An uncontended lock plus unlock is 1 ns (21.5 -> 22.5) slower in C2 compiled code on x64 with the additional increment and decrement.

Fixed aarch64, x64, x86 and zero.

Passes t1-8

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Commit messages:
 - 8286957 - PR Baseline

Changes: https://git.openjdk.org/jdk/pull/8945/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=8945&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8286957
  Stats: 516 lines in 42 files changed: 301 ins; 142 del; 73 mod
  Patch: https://git.openjdk.org/jdk/pull/8945.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/8945/head:pull/8945

PR: https://git.openjdk.org/jdk/pull/8945