Add a flag to dump the current stack trace when emitting a diagnostic.

It is often desirable to know where within the program that a diagnostic was emitted, without reverting to assert/unreachable which crash the program. This change adds a flag `mlir-print-stacktrace-on-diagnostic` that attaches the current stack trace as a note to every diagnostic that gets emitted.

PiperOrigin-RevId: 283996373