RFR: 8354254: Remove the linux ppc64 -minsert-sched-nops=regroup_exact compile flag

[Matthias Baesken]

On linux ppc64 / gcc , we build with the compile flag -minsert-sched-nops=regroup_exact ; this is most likely outdated, maybe it was still useful for old Power6 machines.

See https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/RS_002f6000-and-PowerPC-Options.html
-minsert-sched-nops=scheme : This option controls which NOP insertion scheme is used during the second scheduling pass. The argument scheme takes one of the following values:
‘regroup_exact’ : Insert NOPs to force costly dependent insns into separate groups. Insert exactly as many NOPs as needed to force an insn to a new group, according to the estimated processor grouping.

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Commit messages:
 - JDK-8354254

Changes: https://git.openjdk.org/jdk/pull/24564/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24564&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354254
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/24564.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24564/head:pull/24564

PR: https://git.openjdk.org/jdk/pull/24564