RFR: 8357223: AArch64: Optimize interpreter profile updates

[Chad Rakoczy]

[JDK-8357223](https://bugs.openjdk.org/browse/JDK-8357223)

The aarch64 version of [JDK-8356946](https://bugs.openjdk.org/browse/JDK-8356946)

The reasoning for this change is the same as the x86 version's PR:

> First, we carry the implementation for counter decrements without using them. This is dead code, and can be purged.
> 
> Second, we care about overflows for 64-bit for some reason. I think this is a reminiscent of 32-bit x86 support, where we can plausibly have 32-bit counter overflow in a reasonable timeframe. But for 64-bit counter, we need tens of years of constantly bashing the counter to get it to overflow. No other profile counter update code, e.g. in C1, cares about this.

Additional testing:

- [x] Linux aarch64 fastdebug tier 1/2/3/4

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Commit messages:
 - Give register better name
 - Remove unused code

Changes: https://git.openjdk.org/jdk/pull/25512/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25512&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8357223
  Stats: 47 lines in 2 files changed: 0 ins; 32 del; 15 mod
  Patch: https://git.openjdk.org/jdk/pull/25512.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25512/head:pull/25512

PR: https://git.openjdk.org/jdk/pull/25512