[analyzer] Refactor: Make PathDiagnosticLocation responsible for creating a valid object given an ExploadedNode (the same logic can be reused by other checkers).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139672 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed