Produce direct calls instead of alias to linkonce_odr functions.

This is a small optimization on linux, but should help more on windows
where msvc only outputs one destructor if there would be two identical ones.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194046 91177308-0d34-0410-b5e6-96231b3b80d8