Add the following options:
- -fdebug-measure-parse-tree
- -fdebug-pre-fir-tree
Summary of changes:
- Add 2 new frontend actions: DebugMeasureParseTreeAction and DebugPreFIRTreeAction
- Add MeasurementVisitor to FrontendActions.h
- Make reportFatalSemanticErrors return true if there are any fatal errors
- Port most of the -fdebug-pre-fir-tree tests to use the new driver if built, otherwise use f18