RFR: 8307067: remove broken EnableThreadSMRExtraValidityChecks option [v4]

[Daniel D. Daugherty]

> A trivial fix to remove broken EnableThreadSMRExtraValidityChecks option.

Daniel D. Daugherty has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'master' into JDK-8307067
 - Merge branch 'master' into JDK-8307067
 - dholmes CR - change ':' to '.'.
 - 8307067: remove broken EnableThreadSMRExtraValidityChecks option

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13704/files
  - new: https://git.openjdk.org/jdk/pull/13704/files/a3357b9a..eae82759

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13704&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13704&range=02-03

  Stats: 69279 lines in 798 files changed: 59166 ins; 4592 del; 5521 mod
  Patch: https://git.openjdk.org/jdk/pull/13704.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13704/head:pull/13704

PR: https://git.openjdk.org/jdk/pull/13704