Do not call replaceAllUsesWith to upgrade calls to ARC runtime functions

to intrinsic calls

This fixes a bug in r368311.

It turns out that the ARC runtime functions in the IR can have pointer
parameter types that are not i8* or i8**. Instead of RAUWing normal
functions with intrinsics, manually bitcast the arguments before passing
them to the intrinsic functions and bitcast the return value back to the
type of the original call instruction.

rdar://problem/54125406

llvm-svn: 368634