[PATCH] [Sanitizer] Add Symbolizer::AddHooks() and use it in TSan and MSan.

[Alexey Samsonov]

  I've done sanity testing of this code with actual internal symbolizer implementation, and it looks fine. Submitting this now.

http://llvm-reviews.chandlerc.com/D2067

BRANCH
  svn

ARCANIST PROJECT
  compiler-rt