[PATCH] [asan] Wipe all poisoned memory in fake stack frames before passing them to LSan

[Sergey Matveev]

  This seems to work.

  Can we use the same approach to sanitize real stack? I'm not sure how it would play with non-instrumented code. Does it run on poisoned or unpoisoned stack?

http://llvm-reviews.chandlerc.com/D1962