[TSan] Don't flush all file streams on program shutdown to avoid deadlocks on file stream locks.
This should fix https://code.google.com/p/thread-sanitizer/issues/detail?id=47.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@200922 91177308-0d34-0410-b5e6-96231b3b80d8