RFR: 8292790: Remove hashtable.hpp from other files

Tue Aug 23 17:20:14 UTC 2022

These includes are no longer needed or haven't been needed for a while.  Tested arm cross-compile, and tier1 with Oracle platforms in progress, also GHA.  Please review this change which is trivial if the test results are clean.

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Commit messages:
 - 8292790: Remove hashtable.hpp from other files

Changes: https://git.openjdk.org/jdk/pull/9986/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9986&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292790
  Stats: 10 lines in 8 files changed: 0 ins; 8 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9986.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9986/head:pull/9986

PR: https://git.openjdk.org/jdk/pull/9986