[PATCH] [sanitizer] Fix log_path behavior with StopTheWorld.

[Dmitry Vyukov]

  >Then I think we should make both parent process and tracer task write into the same file.
  I am very confident they must write to a single file.
  User must not generally see tracer output. If there is still some output, then I want to see it intermixed in a single file, to debug the problem. If I run it with verbose, then I want to see output intermixed in a single file.

http://llvm-reviews.chandlerc.com/D2306