RFR: 8329749: Obsolete the unused UseNeon flag [v2]

[Tobias Hartmann]

> After [JDK-8328264](https://bugs.openjdk.org/browse/JDK-8328264), the UseNeon flag is only used by JVMCI code and @dougxc confirmed that it can be removed.
> 
> Thanks,
> Tobias

Tobias Hartmann has updated the pull request incrementally with one additional commit since the last revision:

  Obsoleting the flag

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/18648/files
  - new: https://git.openjdk.org/jdk/pull/18648/files/9da49928..5d8119ab

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18648&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18648&range=00-01

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18648.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18648/head:pull/18648

PR: https://git.openjdk.org/jdk/pull/18648