search for IntelliJ on Mac in /Application and sub folders 1 level deep (#6419)

packages/flutter_tools/lib/src/doctor.dart

@@ -430,8 +430,8 @@ class IntelliJValidatorOnMac extends IntelliJValidator {
 
   static Iterable<DoctorValidator> get installed {
     List<DoctorValidator> validators = <DoctorValidator>[];
-    for (FileSystemEntity dir in new Directory('/Applications').listSync()) {
-      if (dir is Directory) {
+
+    void checkForIntelliJ(Directory dir) {
       String name = path.basename(dir.path);
       _dirNameToId.forEach((String dirName, String id) {
         if (name == dirName) {
@@ -440,6 +440,17 @@ class IntelliJValidatorOnMac extends IntelliJValidator {
         }
       });
     }
+
+    for (FileSystemEntity dir in new Directory('/Applications').listSync()) {
+      if (dir is Directory) {
+        checkForIntelliJ(dir);
+        if (!dir.path.endsWith('.app')) {
+          for (FileSystemEntity subdir in dir.listSync()) {
+            if (subdir is Directory)
+              checkForIntelliJ(subdir);
+          }
+        }
+      }
     }
     return validators;
   }