Make the exit code for dartanalyzer more deterministic.

pkg/analyzer_cli/test/driver_test.dart

Index: pkg/analyzer_cli/test/driver_test.dart
diff --git a/pkg/analyzer_cli/test/driver_test.dart b/pkg/analyzer_cli/test/driver_test.dart
index cc0a1f06a0456edecf7b1574281eb3a13a5e23d0..7af1e3e5bc7200d96d94f313de5c71c70a8f5ec9 100644
--- a/pkg/analyzer_cli/test/driver_test.dart
+++ b/pkg/analyzer_cli/test/driver_test.dart
@@ -66,7 +66,7 @@ main() {
     group('exit codes', () {
       test('fatal hints', () async {
         await drive('data/file_with_hint.dart', args: ['--fatal-hints']);
-        expect(exitCode, 3);
+        expect(exitCode, 1);
       });
 
       test('not fatal hints', () async {
@@ -86,7 +86,7 @@ main() {
 
       test('fatal warnings', () async {
         await drive('data/file_with_warning.dart', args: ['--fatal-warnings']);
-        expect(exitCode, 3);
+        expect(exitCode, 2);
       });
 
       test('not parse enableAssertInitializer', () async {