[analyzer] Add very limited support for temporary destructors

This is an improved version of r186498. It enables ExprEngine to reason about
temporary object destructors.  However, these destructor calls are never
inlined, since this feature is still broken. Still, this is sufficient to
properly handle noreturn temporary destructors.

Now, the analyzer correctly handles expressions like "a || A()", and executes the
destructor of "A" only on the paths where "a" evaluted to false.

Temporary destructor processing is still off by default and one has to
explicitly request it by setting cfg-temporary-dtors=true.

Reviewers: jordan_rose

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1259

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189746 91177308-0d34-0410-b5e6-96231b3b80d8
clang-format: Fix segfault in overloaded operator parsing.

Before, constructs like:
  using A::operator+;

caused a segfault. This fixes llvm.org/PR17050.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189749 91177308-0d34-0410-b5e6-96231b3b80d8