RFR: 8367789: AArch64 missing acquire in JNI_FastGetField::generate_fast_get_int_field0

[Justin King]

Use a load-acquire to match the store-release used by C++ to update `safepoint_counter` during arming.

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Commit messages:
 - JDK-8367789: Use load-acquire instead of load

Changes: https://git.openjdk.org/jdk/pull/27325/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27325&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367789
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/27325.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27325/head:pull/27325

PR: https://git.openjdk.org/jdk/pull/27325