[analyzer] Refactor PathDiagnosticLocation: Use PointerUnion of LocationContext and AnalysisContext to support creation of PathDiagnosticLocations for checkers which no context sensitivity.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140162 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed