Dtor callback emitted when msan attribute not repressed for this function.

Summary: In addition to checking compiler flags, the front-end also examines the attributes of the destructor definition to ensure that the SanitizeMemory attribute is attached.

Reviewers: eugenis, kcc

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D11727

refactored test into new file, revised how function attribute examined

modified test to examine default dtor with and without attribute

removed attribute check

llvm-svn: 243912