Check PHashTranslation generate p_from is valid

(cherry picked from commit 0bb40df4bb65e2c784f29baf4e98d7bf84233804)

core/compressed_translation.cpp

@@ -45,6 +45,7 @@ struct _PHashTranslationCmp {
 
 void PHashTranslation::generate(const Ref<Translation> &p_from) {
 #ifdef TOOLS_ENABLED
+	ERR_FAIL_COND(p_from.is_null());
 	List<StringName> keys;
 	p_from->get_message_list(&keys);