Use only one message for NDK discovery, remove accidental newline (#13348)

packages/flutter_tools/lib/src/android/android_workflow.dart

@@ -120,13 +120,9 @@ class AndroidWorkflow extends DoctorValidator implements Workflow {
     messages.add(new ValidationMessage('Android SDK at ${androidSdk.directory}'));
 
     messages.add(new ValidationMessage(androidSdk.ndkDirectory == null
-          ? 'Unable to locate Android NDK.\n'
+          ? 'Android NDK location not configured (this optional configuration is useful for native profiling support)'
           : 'Android NDK at ${androidSdk.ndkDirectory}'));
 
-    messages.add(new ValidationMessage(androidSdk.ndkCompiler == null
-          ? 'Unable to locate compiler in Android NDK.\n'
-          : 'Compiler in Android NDK at ${androidSdk.ndkCompiler}'));
-
     String sdkVersionText;
     if (androidSdk.latestVersion != null) {
       sdkVersionText = 'Android SDK ${androidSdk.latestVersion.buildToolsVersionName}';