[drmemtrace] raw2trace should print more diagnostics upfront on fatal errors

Debugging a failed raw2trace run sometimes requires getting the offline_entry_t entries from the raw trace files. This requires one to know: the thread id that hit the error, the last timestamp seen, and the raw trace entry hex (the "combined" entry). All fatal raw2trace errors should print this information to obviate the need to rerun raw2trace with diagnostics.

Also, it would be even better if raw2trace can print out surrounding raw trace entries too, obviating the need to manually look into the raw files at all.