[analyzer] Make NodeBuilder and Pred node loosely coupled

NodeBuilder should not assume it's dealing with a single predecessor. Remove predecessor getters. Modify the BranchNodeBuilder to not be responsible for doing auto-transitions (which depend on a predecessor).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142453 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed