These ExprWithCleanups are added for holding a RunCleanupsScope not
for destructor calls; rather, they are for lifetime marks. This requires
ExprWithCleanups to keep a bit to indicate whether it have cleanups with
side effects (e.g. dtor calls).

Differential Revision: http://reviews.llvm.org/D20498

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@272296 91177308-0d34-0410-b5e6-96231b3b80d8