[llvm] [SelectionDAG] Fix null pointer dereference in resolveDanglingDebugInfo (PR #174341)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> I think the intended use of `not --crash` is to check for controlled crashes (e.g., `report_fatal_error`), not cases like this where it looks like something is dereferencing a null/invalid pointer.

--crash should not be necessary for controlled crashes. That is an uncontrolled crash with a backtrace. report_fatal_error should not be used anymore, and reportFatalUsageError in its place which doesn't throw the backtrace with negative error 


https://github.com/llvm/llvm-project/pull/174341