[jdk17] RFR: 8268739: AArch64: Build failure after JDK-8267663

[Eric Liu]

The failure is cased by the build option "--with-jvm-variants=client".
In client mode, BoolTest[1] is used by "neon_compare"[2] but not
declared in macroAssembler_aarch64.hpp[3].

Since "neon_compare" is c2 specific, this patch moves it to
c2_MacroAssembler_aarch64.cpp.

[1] https://github.com/openjdk/jdk17/blob/master/src/hotspot/share/opto/subnode.hpp#L308
[2] https://github.com/openjdk/jdk17/blob/master/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp#L5342
[3] https://github.com/openjdk/jdk17/blob/master/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp#L58

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Commit messages:
 - 8268739: AArch64: Build failure after JDK-8267663

Changes: https://git.openjdk.java.net/jdk17/pull/73/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17&pr=73&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268739
  Stats: 94 lines in 4 files changed: 47 ins; 45 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/73.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/73/head:pull/73

PR: https://git.openjdk.java.net/jdk17/pull/73