RFR: 8308479: [s390x] Implement alternative fast-locking scheme [v3]

[Amit Kumar]

> This PR implements new fast-locking scheme for s390x. Additionally few parameters have been renamed to be in sync with PPC.
> 
> Testing done (for release, fastdebug and slowdebug build):
> All `test/jdk/java/util/concurrent` test with parameters:
> * LockingMode=2 
> * LockingMode=2 with -Xint
> * LockingMode=2 with -XX:TieredStopAtLevel=1
> * LockingMode=2 with -XX:-TieredCompilation
> 
> Result is consistently similar to Aarch(MacOS) and PPC, All of 124 tests are passing except `MapLoops.java` because in the 2nd part for this testcase, jvm starts with `HeavyMonitors` which conflict with `LockingMode=2`

Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:

  restore currentHeader after z_nill

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14414/files
  - new: https://git.openjdk.org/jdk/pull/14414/files/c849926d..1035c90d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14414&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14414&range=01-02

  Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/14414.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14414/head:pull/14414

PR: https://git.openjdk.org/jdk/pull/14414