Allow a standard library to implement conditional noexcept for optional and...

Allow a standard library to implement conditional noexcept for optional and unique_ptr hash functions.

These tests were unconditionally asserting that optional and unique_ptr declare throwing hashes, but MSVC++ implements conditional noexcept forwarding that of the underlying hash function. As a result we were failing these tests but there's nothing forbidding strengthening noexcept in that way.

Changed the ASSERT_NOT_NOEXCEPT asserts to use types which themselves have non-noexcept hash functions.

llvm-svn: 299734