[arcmt] Remove the "it is not safe to remove an unused 'autorelease' message" ARC
migration error.

This is more trouble that it is worth; autoreleasing a value without holding on it
is a valid use-case, we should not "punish" correct code for the minority of
broken/fragile programs that depend on the behavior of  -autorelease.

rdar://9914061

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156999 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed