Removed special cases for '.exe'.

packages/flutter_tools/lib/src/artifacts.dart

@@ -159,10 +159,6 @@ class CachedArtifacts extends Artifacts {
         // android_arm in profile mode because it is available on all supported host platforms.
         return _getAndroidArtifactPath(artifact, TargetPlatform.android_arm, BuildMode.profile);
       case Artifact.flutterTester:
-        final String engineArtifactsPath = cache.getArtifactDirectory('engine').path;
-        final String platformDirName = getNameForTargetPlatform(platform);
-        String path = fs.path.join(engineArtifactsPath, platformDirName, _artifactToFileName(artifact));
-        return (platform == TargetPlatform.windows_x64) ? (path + '.exe') : path;
       case Artifact.vmSnapshotData:
       case Artifact.isolateSnapshotData:
       case Artifact.frontendServerSnapshotForEngineDartSdk:
@@ -283,8 +279,6 @@ class LocalEngineArtifacts extends Artifacts {
       return fs.path.join(engineOutPath, _artifactToFileName(Artifact.flutterTester));
     } else if (getCurrentHostPlatform() == HostPlatform.darwin_x64) {
       return fs.path.join(engineOutPath, 'flutter_tester');
-    } else if (getCurrentHostPlatform() == HostPlatform.windows_x64) {
-      return fs.path.join(engineOutPath, 'flutter_tester.exe');
     }
     throw new Exception('Unsupported platform $platform.');
   }

packages/flutter_tools/lib/src/test/runner.dart

@@ -11,6 +11,7 @@ import '../artifacts.dart';
 import '../base/common.dart';
 import '../base/file_system.dart';
 import '../base/io.dart';
+import '../base/process_manager.dart';
 import '../base/terminal.dart';
 import '../dart/package_map.dart';
 import '../globals.dart';
@@ -61,7 +62,7 @@ Future<int> runTests(
 
   // Configure package:test to use the Flutter engine for child processes.
   final String shellPath = artifacts.getArtifactPath(Artifact.flutterTester);
-  if (!fs.isFileSync(shellPath))
+  if (!processManager.canRun(shellPath))
     throwToolExit('Cannot find Flutter shell at $shellPath');
 
   final InternetAddressType serverType =