Fix some cases of incorrect handling of lifetime extended temporaries.

MaterializeTemporaryExpr already contains information about the lifetime
of the temporary; if the lifetime is not the full statement, we do not
want to emit a destructor at the end of the full statement for it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214292 91177308-0d34-0410-b5e6-96231b3b80d8