When #pragma clang __debug crash is used, currently Driver::generateCompilationDiagnostics() doesn't work. The clang -E created for diagnostics would crash again, because it reaches Pragma.cpp, L1043 again.
We simply disable the intended crashing behavior with a new cc1 flag -disable-pragma-debug-crash.
- #pragma clang __debug llvm_report_fatal isn't currently tested below, because it needs exit() to be handled differently in -fintegrated-cc1 mode.
- This patch is also needed to further test that -MF is removed from the gen crash diagnostic cmd-line (currently not the case).
This patch is point 1. in D73742