RFR: 8256569: Add C2 compiler stress flags to CTW [v2]

[Igor Ignatyev]

> Hi all,
> 
> Could you please review this small patch which adds `-XX:+StressLCM`, `-XX:+StressGCM`, and `-XX:+StressIGVN` flags to the CTW test library? these flags have been found instrumental in increasing the probability to find C2 bugs. The patch also specifies `-XX:StressSeed` flag to keep CTW testing deterministic and reproducible.
> 
> testing:
> * [x] `test/hotspot/jtreg/applications/ctw/modules/java_base.java` on `macos-x64`
> * [x] `test/hotspot/jtreg/testlibrary_tests/ctw/` on `macos-x64`
> 
> Cheers,
> -- Igor

Igor Ignatyev has updated the pull request incrementally with one additional commit since the last revision:

  updated copyright year

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1332/files
  - new: https://git.openjdk.java.net/jdk/pull/1332/files/9201384b..f470020f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1332&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1332&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1332.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1332/head:pull/1332

PR: https://git.openjdk.java.net/jdk/pull/1332