[analyzer] Add another exception for Qt in MallocChecker

Treat pointers passed to QObject::connectImpl() as escaping.

rdar://problem/29550440

Differential Revision: https://reviews.llvm.org/D27717

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289939 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 7c595b6e32a15db71e28cd65408a8b90f35302cf)
3 files changed