RFR: 8356556: AArch64: No need for acquire fence in safepoint poll in FFM

[Anton Artemov]

Hi, please consider the following changes:

On AArch64, the `acquire` bool argument of the `safepoint_poll()` method is removed, as the load-acquire `ldar` instruction in the `safepoint_poll()` implementation is not needed completely. It was used for observing the disarmed value when VMThread was used to disarm the Java threads, but currently JavaThreads disarm themselves. 

Tested in tiers 1 - 4.

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Commit messages:
 - 8356556: Fixed whitespaces.
 - 8356556: Fixed trailing whitespace.
 - 8356556: Removed acquire argument from safepoint_poll on aarch64

Changes: https://git.openjdk.org/jdk/pull/25829/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25829&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8356556
  Stats: 17 lines in 8 files changed: 0 ins; 3 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/25829.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25829/head:pull/25829

PR: https://git.openjdk.org/jdk/pull/25829