RFR: 8271118: C2: StressGCM should have higher priority than frequency-based policy [v3]

[Yi Yang]

> I think StressGCM should have higher priority than frequency-based policy, otherwise StressGCM has no chance to choose because the frequency-based policy would choose block first if appropriately.

Yi Yang has updated the pull request incrementally with one additional commit since the last revision:

  review from kvn

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4865/files
  - new: https://git.openjdk.java.net/jdk/pull/4865/files/299d4b95..c3964f20

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4865&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4865&range=01-02

  Stats: 22 lines in 1 file changed: 5 ins; 6 del; 11 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4865.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4865/head:pull/4865

PR: https://git.openjdk.java.net/jdk/pull/4865