[msan] Fix origin of deallocated memory.

MSan poisons deallocated memory but it used to give it an invalid origin value,
resulting in confusing reports. This change associates deallocation stack trace
with such memory.

Note that MSan does not have quarantine, and use-after-free detection is very
limited.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190781 91177308-0d34-0410-b5e6-96231b3b80d8