RFR: 8361092: Remove trailing spaces in x86 ad files

[Manuel Hässig]

This PR fixes some trailing spaces in `x86_64.ad`.

Testing:
 - [ ] Github Actions

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Commit messages:
 - Fix trailing spaces

Changes: https://git.openjdk.org/jdk/pull/26048/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26048&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8361092
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/26048.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26048/head:pull/26048

PR: https://git.openjdk.org/jdk/pull/26048