Failing test highlighting no poisoning if dtor undeclared.

Summary:
If class or struct has not declared a destructor,
no destructor is emitted, and members are not poisoned
after destruction. This case highlights bug in current
implementation of use-after-dtor poisoning (detailed
in https://github.com/google/sanitizers/issues/596).

Reviewers: eugenis, kcc

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D12616

Only check simplest object for existence of sanitizing callback.

Rename test.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@247025 91177308-0d34-0410-b5e6-96231b3b80d8