[analyzer] Malloc checker should only escape the receiver when “[O init..]” is called.

Jordan has pointed out that it is valuable to warn in cases when the arguments to init escape.
For example, NSData initWithBytes id not going to free the memory.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@183062 91177308-0d34-0410-b5e6-96231b3b80d8