RFR: 8367899: compiler/c2/gvn/TestBitCompressValueTransform.java intermittent timed out

[SendaoYan]

Hi all,

After JDK-8260555 change the timeout factor from 4 to 1, make test compiler/c2/gvn/TestBitCompressValueTransform.java intermittent timed out.

There are 20 10k/20k loop count of loops in this test, this cause test need many CPU cycles to finish. If I reduce the loop count from 10k/20k to 100/200, the test failures descripted in [JDK-8350896](https://bugs.openjdk.org/browse/JDK-8350896) also reproduced when the tested jdk is jdk25u. So it seems that there no need so many loop count for these tests.

Without the proposed change, the driver action finish about 65 sencods on linux-x64, with the proposed change the driver action finish about 1.5 seconds.

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Commit messages:
 - 8367899: compiler/c2/gvn/TestBitCompressValueTransform.java intermittent timed out

Changes: https://git.openjdk.org/jdk/pull/27548/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27548&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367899
  Stats: 20 lines in 1 file changed: 0 ins; 0 del; 20 mod
  Patch: https://git.openjdk.org/jdk/pull/27548.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27548/head:pull/27548

PR: https://git.openjdk.org/jdk/pull/27548