Remove Compiler.mainApp and Compiler.mainFunction

tests/compiler/dart2js/serialization/model_test_helper.dart

Index: tests/compiler/dart2js/serialization/model_test_helper.dart
diff --git a/tests/compiler/dart2js/serialization/model_test_helper.dart b/tests/compiler/dart2js/serialization/model_test_helper.dart
index 0dd3d17525bba2180754576841763c539dc6e03b..12ac3362c31449ad94a0fa54e5da8ab46f3e2f7d 100644
--- a/tests/compiler/dart2js/serialization/model_test_helper.dart
+++ b/tests/compiler/dart2js/serialization/model_test_helper.dart
@@ -9,6 +9,7 @@ import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/closure.dart';
 import 'package:compiler/src/commandline_options.dart';
+import 'package:compiler/src/common_elements.dart';
 import 'package:compiler/src/constants/values.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/deferred_load.dart';
@@ -71,7 +72,9 @@ Future checkModels(Uri entryPoint,
         memorySourceFiles: sourceFiles, options: [Flags.analyzeOnly]);
     compilerNormal.resolution.retainCachesForTesting = true;
     await compilerNormal.run(entryPoint);
-    compilerNormal.closeResolution();
+    ElementEnvironment elementEnvironment =
+        compilerNormal.frontendStrategy.elementEnvironment;
+    compilerNormal.closeResolution(elementEnvironment.mainFunction);
     return compilerNormal;
   });
 
@@ -83,7 +86,9 @@ Future checkModels(Uri entryPoint,
         options: [Flags.analyzeOnly]);
     compilerDeserialized.resolution.retainCachesForTesting = true;
     await compilerDeserialized.run(entryPoint);
-    compilerDeserialized.closeResolution();
+    ElementEnvironment elementEnvironment =
+        compilerDeserialized.frontendStrategy.elementEnvironment;
+    compilerDeserialized.closeResolution(elementEnvironment.mainFunction);
     return compilerDeserialized;
   });