[docs] Add some architectures into the list of supported ThreadSanitizer platforms
Some platforms for which TSAN has build rules are omitted for the lack of
known build bots.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@355445 91177308-0d34-0410-b5e6-96231b3b80d8
Vitaly Buka