[analyzer] Convert ExprEngine::visit() to use short lived builders.

[analyzer] Convert ExprEngine::visit() to use short lived builders.

This commit removes the major functional dependency on the ExprEngine::Builder
member variable.

In some cases the code became more verbose. Particularly, we call takeNodes()
and addNodes() to move responsibility for the nodes from one builder to another.
This will get simplified later on.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142831 91177308-0d34-0410-b5e6-96231b3b80d8