RFR: 8302191: Performance degradation for float/double modulo on Linux

[Jan Kratochvil]

I have OCA already processed/approved. I am not Author but my Author request is being processed these days (sent to Rob McKenna).
I did regression test x86_64 OpenJDK-8. I will leave other regression testing on GHA.
The patch (and former GCC performance regression) affects only x86_64+i686.

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Commit messages:
 - 8302191: Performance degradation for float/double modulo on Linux

Changes: https://git.openjdk.org/jdk/pull/12508/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12508&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302191
  Stats: 31 lines in 1 file changed: 29 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12508.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12508/head:pull/12508

PR: https://git.openjdk.org/jdk/pull/12508