Suppress verbose output from ios-deploy when not in verbose mode. (#4423)

packages/flutter_tools/lib/src/base/process.dart

@@ -29,6 +29,7 @@ Future<Process> runCommand(List<String> cmd, { String workingDirectory }) async
 Future<int> runCommandAndStreamOutput(List<String> cmd, {
   String workingDirectory,
   String prefix: '',
+  bool trace: false,
   RegExp filter,
   StringConverter mapFunction
 }) async {
@@ -40,8 +41,13 @@ Future<int> runCommandAndStreamOutput(List<String> cmd, {
     .listen((String line) {
       if (mapFunction != null)
         line = mapFunction(line);
-      if (line != null)
-        printStatus('$prefix$line');
+      if (line != null) {
+        String message = '$prefix$line';
+        if (trace)
+          printTrace(message);
+        else
+          printStatus(message);
+      }
     });
   process.stderr
     .transform(UTF8.decoder)

packages/flutter_tools/lib/src/ios/devices.dart

@@ -203,7 +203,7 @@ class IOSDevice extends Device {
       '--bundle',
       bundle.path,
       '--justlaunch',
-    ]);
+    ], trace: true);
 
     if (installationResult != 0) {
       printError('Could not install ${bundle.path} on $id.');