[objc_direct] Allow for direct messages be sent to self when it is a Class
Sending a message to self when it is const and within a class method
is safe because we know that self is the Class itself.
We can only relax this warning in ARC.
Signed-off-by: Pierre Habouzit <email@example.com>
Differential Revision: https://reviews.llvm.org/D72747
(cherry picked from commit 7596d3c50c4b265612d326369e2a015cf8c60801)