Revert r254417 ("[tsan] Enable Thread Sanitizer on OS X builds by default").
Revert r254417 ("[tsan] Enable Thread Sanitizer on OS X builds by default").

A ton of tests fail on OS X 10.10, because dyld auto-interposition is only available in 10.11.



git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@254420 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt