RFR: 8273915: Create 'nosafepoint' rank [v3]

[Coleen Phillimore]

> Partition safepoint checking and nonchecking lock ranks. The nonchecking locks are always lower ranked than the safepoint checking locks because they cannot block.
> 
> This moves some leaf locks to 'nosafepoint' rank and corrects relative ranking.
> 
> Tested with tier1-6 and built and run tier1 tests with shenandoah locally.

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

  Add comment and change enum name to Rank.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5550/files
  - new: https://git.openjdk.java.net/jdk/pull/5550/files/1a927805..f85c647f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5550&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5550&range=01-02

  Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5550.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5550/head:pull/5550

PR: https://git.openjdk.java.net/jdk/pull/5550