[analyzer] Handle base class initializers and destructors.

Most of the logic here is fairly simple; the interesting thing is that
we now distinguish complete constructors from base or delegate constructors.
We also make sure to cast to the base class before evaluating a constructor
or destructor, since non-virtual base classes may behave differently.

This includes some refactoring of VisitCXXConstructExpr and VisitCXXDestructor
in order to keep ExprEngine.cpp as clean as possible (leaving the details for
ExprEngineCXX.cpp).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160806 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed