Test triangle inheritance member poisoning.

Summary: Verify that all members are poisoned.

Reviewers: eugenis, kcc

Differential Revision: http://reviews.llvm.org/D12023

Test virtual functions and virtual bases poisoning proper size.

Runtime testing of destroying diamond inheritance.

Explicit testing for 0 optimizations.

Simplify test to only test interesting values.

Test poisoning on multiple inheritance with nontrivial and trivial members.

Removed unnecessary header.

Testing (anonymous/)bit fields.

Revised object instantiation in test to avoid undefined behavior.

llvm-svn: 246817