RFR: 8311964 : Some jtreg tests failing on x86 with error 'unrecognized VM options' (C2 flags)

[nitinsingh130519]

This commit addresses the issue of failing jtreg tests on the x86 platform. The tests were failing due to unrecognized VM options 'LoopUnswitching', 'OptimizeFill' and 'StressCCP' which are not available in x86 binary. 

Following tests were affected: 

1. TestInfiniteLoopWithUnmergedBackedgesMain.java - Affected by 'LoopUnswitching'
2. TestBackedgeLoadArrayFillMain.java - Affected by 'OptimizeFill'
3. TestRangeCheckCmpUOverflowVsSub.java - Affected by 'StressCCP'

Changes have been made to these tests to avoid the use of these flags when testing on x86. 

These changes maintain the integrity of the tests while ensuring compatibility across different platforms.

Related commits: 

- [ee63f83ed705c9cd3c49316fc4936668744f415d](https://github.com/microsoft/openjdk-jdk17u/commit/ee63f83ed705c9cd3c49316fc4936668744f415d#diff-ac9e408e8f32ed8c6260b005b8c386bc7a0a8738a8b8d2fe91c82b66f9f6ab7e)
- [d21597aec91bbd41960923385f6a1feb31f14a0c](https://github.com/microsoft/openjdk-jdk17u/commit/d21597aec91bbd41960923385f6a1feb31f14a0c)
- [e6c27925d23fe283a23c6adbe263658909c3739d](https://github.com/microsoft/openjdk-jdk17u/commit/e6c27925d23fe283a23c6adbe263658909c3739d#diff-36a07bd10ab86c032882232a1d18b96fb6a399c01dc05739c24ea12e9abc2d55)

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Commit messages:
 - Fix failing jtreg tests due to missing c2 flags on x86

Changes: https://git.openjdk.org/jdk/pull/14942/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14942&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8311964
  Stats: 3 lines in 3 files changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14942.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14942/head:pull/14942

PR: https://git.openjdk.org/jdk/pull/14942