tsan: better report for bad mutex unlocks
+ fixes crashes due to races on symbolizer, see
https://code.google.com/p/thread-sanitizer/issues/detail?id=55



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@207206 91177308-0d34-0410-b5e6-96231b3b80d8
tsan: fix tests
failure:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-centos-6.5/builds/3747/steps/test/logs/stdio



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@207207 91177308-0d34-0410-b5e6-96231b3b80d8
tsan: improve "read unlock of a write locked mutex" report



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@207208 91177308-0d34-0410-b5e6-96231b3b80d8