auto-t: do away with -1 test results

This can result in strange test results since there was no less
than zero checks before subtracting the total tests from failed
tests. In case of an internal exception we can just set all values
to zero. This will be handled specially as we do for timeout
errors.

tools/test-runner

@@ -973,16 +973,20 @@ def print_results(results):
 	total_time = 0
 
 	for test, result in results.items():
-		if result.time != TEST_MAX_TIMEOUT:
+
+		if result.time == TEST_MAX_TIMEOUT:
+			failed = "Timed out"
+			passed = "Timed out"
+		elif result.time == 0:
+			failed = "Exception"
+			passed = "Exception"
+		else:
 			failed = result.failures + result.errors
 			passed = result.run - failed
 
 			total_pass += passed
 			total_fail += failed
 			total_skip += result.skipped
-		else:
-			failed = "Timed out"
-			passed = "Timed out"
 
 		total_time += result.time
 
@@ -1046,8 +1050,8 @@ def run_auto_tests(ctx, args):
 		except Exception as ex:
 			print(ex)
 			print("Uncaught exception thrown for %s" % test)
-			ctx.results[os.path.basename(test)] = SimpleResult(run=-1, failures=-1,
-								errors=-1, skipped=-1, time=-1)
+			ctx.results[os.path.basename(test)] = SimpleResult(run=0, failures=0,
+								errors=0, skipped=0, time=0)
 		finally:
 			post_test(ctx, copied)