RFR: 8364296: Set IntelJccErratumMitigation flag ergonomically

[Oli Gillespie]

We should update the flag if we are using a computed value. Nobody else reads IntelJccErratumMitigation specifically, but we want it to be correctly shown in PrintFlagsFinal and anywhere else these flags are inspected.


Intel(R) Xeon(R) Platinum 8259CL
java -XX:+UnlockDiagnosticVMOptions -XX:+PrintFlagsFinal -version | grep IntelJcc
Before:
     bool IntelJccErratumMitigation  = true   {ARCH diagnostic} {default}
After:
     bool IntelJccErratumMitigation  = true   {ARCH diagnostic} {ergonomic}


Even worse when it's actually false, but shows as true:


AMD EPYC 7R13
java -XX:+UnlockDiagnosticVMOptions -XX:+PrintFlagsFinal -version | grep IntelJcc
Before:
     bool IntelJccErratumMitigation  = true   {ARCH diagnostic} {default}
After:
     bool IntelJccErratumMitigation  = false  {ARCH diagnostic} {ergonomic}

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Commit messages:
 - Set IntelJccErratumMitigation ergonomically

Changes: https://git.openjdk.org/jdk/pull/26560/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26560&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364296
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26560.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26560/head:pull/26560

PR: https://git.openjdk.org/jdk/pull/26560