Make inference defaults consts for easy tweaking

lib/src/testing.dart

Index: lib/src/testing.dart
diff --git a/lib/src/testing.dart b/lib/src/testing.dart
index 980bfbc958bd71d81fefccc95115d2842b5653d9..bd1a328f78da0b18011afd47579c72a4323f5413 100644
--- a/lib/src/testing.dart
+++ b/lib/src/testing.dart
@@ -50,8 +50,9 @@ import 'package:dev_compiler/devc.dart' show Compiler;
 CheckerResults testChecker(Map<String, String> testFiles,
     {bool allowConstCasts: true, String sdkDir, CheckerReporter reporter,
     covariantGenerics: true, relaxedCasts: true,
-    inferFromOverrides: ResolverOptions.INFER_FROM_OVERRIDES_DEFAULT,
-    inferStaticsFromIdentifiers: false, inferInNonStableOrder: false,
+    inferFromOverrides: ResolverOptions.inferFromOverridesDefault,
+    inferStaticsFromIdentifiers: ResolverOptions.inferStaticsFromIdentifiersDefault,
+    inferInNonStableOrder: ResolverOptions.inferInNonStableOrderDefault,
     nonnullableTypes: TypeOptions.NONNULLABLE_TYPES}) {
   expect(testFiles.containsKey('/main.dart'), isTrue,
       reason: '`/main.dart` is missing in testFiles');