Re-enable weak webdev tests (#1960)

* Validate only needed summaries in expression_compiler_service

* Move shared test functionality into test_common package

* Rebase on master

* Fix bad merge

* Re-enable webdev weak null safety e2e tests

Author: Anna Gringauze

Diff for: webdev/pubspec.yaml

@@ -45,6 +45,8 @@ dev_dependencies:
   build_verify: ^3.0.0
   build_version: ^2.1.1
   test: ^1.21.1
+  test_common:
+    path: ../test_common
   test_descriptor: ^2.0.0
   test_process: ^2.0.2
   webdriver: ^3.0.0

Diff for: webdev/test/e2e_test.dart

@@ -180,8 +180,7 @@ void main() {
       await process.shouldExit(0);
 
       await d.file('main.unsound.ddc.js', isNotEmpty).validate();
-      // 'https://github.com/dart-lang/webdev/issues/1892'
-    }, skip: true);
+    });
   });
 
   group('should build with --output=NONE', () {
@@ -507,8 +506,7 @@ void main() {
             }
           }, timeout: const Timeout.factor(2));
         });
-        // 'https://github.com/dart-lang/webdev/issues/1892'
-      }, skip: !soundNullSafety);
+      });
     }
   });
 }

Diff for: webdev/test/test_utils.dart

@@ -7,13 +7,18 @@ import 'dart:io';
 
 import 'package:path/path.dart' as p;
 import 'package:test/test.dart';
+import 'package:test_common/test_sdk_configuration.dart';
 import 'package:test_process/test_process.dart';
 import 'package:webdev/src/util.dart';
 
 final _webdevBin = p.absolute(p.join('bin', 'webdev.dart'));
+final _sdkConfigurationProvider = TestSdkConfigurationProvider();
 
 Future<TestProcess> runWebDev(List<String> args,
     {String? workingDirectory}) async {
+  // Generate missing test assets in the SDK.
+  await _sdkConfigurationProvider.configuration;
+
   var fullArgs = [_webdevBin, ...args];
 
   return TestProcess.start(dartPath, fullArgs,