[CodeGen][CXX]: Fix no_destroy CG bug under specific circumstances

Summary:

Class with no user-defined destructor that has an inherited member that has a
non-trivial destructor and a non-default constructor will attempt to emit a
destructor despite being marked as __attribute((no_destroy)) in which case it
would trigger an assertion due to an incorrect assumption. 

In addition this adds missing test coverage for IR generation for no_destroy.

(Note that here use of no_destroy is synonymous with its global flag 
counterpart `-fno-c++-static-destructors` being enabled)

Differential Revision: https://reviews.llvm.org/D54344

llvm-svn: 346628