RFR: 8313530: VM build without C2 fails after JDK-8312579

Tue Aug 22 09:10:56 UTC 2023

The EnableVectorSupport flag is declared in `opto/c2_globals.hpp`, which is not included if `COMPILER2` is not set. But after my changes for [JDK-8312579](https://bugs.openjdk.org/browse/JDK-8312579) we try to access this flag in some places guarded by `#if COMPILER2_OR_JVMCI`.

This PR moves some flags from `c2_globals.hpp` to the shared `compiler_globals.hpp`, so that they are accessible even if C2 is disabled but JVMCI is enabled.

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Commit messages:
 - 8313530: VM build without C2 fails after JDK-8312579

Changes: https://git.openjdk.org/jdk/pull/15384/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15384&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313530
  Stats: 26 lines in 2 files changed: 14 ins; 12 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15384.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15384/head:pull/15384

PR: https://git.openjdk.org/jdk/pull/15384