b492ec5899
This implements the result of the discussion at: https://discourse.llvm.org/t/rfc-report-fatal-error-and-the-default-value-of-gencrashdialog/73587 There are two different use cases for report_fatal_error, so replace it with two functions reportFatalInternalError() and reportFatalUsageError(). The former indicates a bug in LLVM and generates a crash dialog. The latter does not. The names have been suggested by rnk and people seemed to like them. This replaces a lot of the usages that passed an explicit value for GenCrashDiag. I did not bulk replace remaining report_fatal_error usage -- they probably require case by case review for which function to use.