RFR: Allow creating branches with /branch commit command

[Man Cao]

Hello,

Could anyone approve this change to allow creating branches in the TSAN project? See https://bugs.openjdk.org/browse/SKARA-2345 and https://bugs.openjdk.org/browse/JDK-8333743.

-Man

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Commit messages:
 - Allow creating branches with /branch commit command

Changes: https://git.openjdk.org/tsan/pull/22/files
  Webrev: https://webrevs.openjdk.org/?repo=tsan&pr=22&range=00
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/tsan/pull/22.diff
  Fetch: git fetch https://git.openjdk.org/tsan.git pull/22/head:pull/22

PR: https://git.openjdk.org/tsan/pull/22