Always identify test names that lead to failures

recipe_engine/test_result.proto

Index: recipe_engine/test_result.proto
diff --git a/recipe_engine/test_result.proto b/recipe_engine/test_result.proto
index 25ac5f72261630904b298cfca5029cb4fd6cdd89..281c28d100346316fefba90e29a6159710b3e770 100644
--- a/recipe_engine/test_result.proto
+++ b/recipe_engine/test_result.proto
@@ -51,11 +51,19 @@ message TestResult {
     int64 lineno = 6;
   }
 
+  // An internal failure (either ctrl-c interruption, or an exception
+  // while running the test; this could mean a crashing recipe execution,
+  // or even failure in the test runner itself).
+  message InternalFailure {
+  }
+
   message TestFailure {
     oneof failures {
       DiffFailure diff_failure = 1;
 
       CheckFailure check_failure = 2;
+
+      InternalFailure internal_failure = 3;
     }
   }