RFR: 8272797: Mutex with rank safepoint_check_never imply allow_vm_block [v2]

[Coleen Phillimore]

> See CR for details.  This essentially makes Mutex that safepoint_check_never imply a NoSafepointVerifier, which is a stronger and simpler invariant.
> Tested with tier1-6.

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Add simple gtest.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5218/files
  - new: https://git.openjdk.java.net/jdk/pull/5218/files/e7e70f1a..fb83fe81

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5218&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5218&range=00-01

  Stats: 10 lines in 1 file changed: 10 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5218.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5218/head:pull/5218

PR: https://git.openjdk.java.net/jdk/pull/5218