Update ObjCContainersChecker to be notified when pointers escape so it can
remove size information for escaping CFMutableArrayRefs. When such pointers
escape, un-analyzed code could mutate the array and cause the size information
to be incorrect.

rdar://problem/19406485


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@239709 91177308-0d34-0410-b5e6-96231b3b80d8