RFR: 8292187: aarch64: Remove duplicate header files

[Feilong Jiang]

It's a trivial patch that removes duplicate included header files under hotspot/cpu/aarch64.

aarch64 release and fastdebug build with `--disable-precompiled-headers` passed.

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Commit messages:
 - Remove duplicate header files

Changes: https://git.openjdk.org/jdk/pull/9821/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9821&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292187
  Stats: 8 lines in 3 files changed: 1 ins; 7 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/9821.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9821/head:pull/9821

PR: https://git.openjdk.org/jdk/pull/9821