Revert r172719, r172721-172723, and r172725.

The r172719 patch broke the build on Mac, the others depended on it.

compiler-rt/lib/asan/asan_interceptors.cc:78:13: error: unused function
      'SetThreadName' [-Werror,-Wunused-function]
      static void SetThreadName(const char *name) {

Orignal headlines:

  [asan] attempting to fix the Mac build
  [asan] restructure read/pread/pread64 tests
  [sanitizer] move write/pwrite/pwrite64 interceptors to common
  [msan] start using common interceptors in msan
  [tsan] move prctl interceptor from asan to common_interceptors thus enabling it for tsan too

llvm-svn: 172763