RFR: 8307067: remove broken EnableThreadSMRExtraValidityChecks option [v2]

[Daniel D. Daugherty]

> A trivial fix to remove broken EnableThreadSMRExtraValidityChecks option.

Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:

  dholmes CR - change ':' to '.'.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13704/files
  - new: https://git.openjdk.org/jdk/pull/13704/files/bfb24496..59f7a22e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13704&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13704&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 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