Fix the doctor check for the flutter intellij plugin (#12389)

* update the intellij doctor check to support the m18 plugin version

* update to support multiple package names

packages/flutter_tools/lib/src/doctor.dart

@@ -269,9 +269,9 @@ abstract class IntelliJValidator extends DoctorValidator {
   Future<ValidationResult> validate() async {
     final List<ValidationMessage> messages = <ValidationMessage>[];
 
-    _validatePackage(messages, 'flutter-intellij.jar', 'Flutter',
-        minVersion: kMinFlutterPluginVersion);
-    _validatePackage(messages, 'Dart', 'Dart');
+    _validatePackage(messages, <String>['flutter-intellij', 'flutter-intellij.jar'],
+        'Flutter', minVersion: kMinFlutterPluginVersion);
+    _validatePackage(messages, <String>['Dart'], 'Dart');
 
     if (_hasIssues(messages)) {
       messages.add(new ValidationMessage(
@@ -309,15 +309,14 @@ abstract class IntelliJValidator extends DoctorValidator {
     }
   }
 
-  void _validatePackage(List<ValidationMessage> messages, String packageName, String title, {
+  void _validatePackage(List<ValidationMessage> messages, List<String> packageNames, String title, {
     Version minVersion
   }) {
+    for (String packageName in packageNames) {
       if (!hasPackage(packageName)) {
-      messages.add(new ValidationMessage.error(
-        '$title plugin not installed; this adds $title specific functionality.'
-      ));
-      return;
+        continue;
       }
+
       final String versionText = _readPackageVersion(packageName);
       final Version version = new Version.parse(versionText);
       if (version != null && minVersion != null && version < minVersion) {
@@ -329,6 +328,13 @@ abstract class IntelliJValidator extends DoctorValidator {
           '$title plugin ${version != null ? "version $version" : "installed"}'
         ));
       }
+
+      return;
+    }
+
+    messages.add(new ValidationMessage.error(
+      '$title plugin not installed; this adds $title specific functionality.'
+    ));
   }
 
   String _readPackageVersion(String packageName) {