Re-enable use of instruments for iOS device lookup (#10838)

This reverts commit b2909a245a607995ce7ec286585cd1f643124f57.

This resubmits the following patches:

1. Use Xcode instruments to list devices (#10801)
Eliminates the dependency on idevice_id from libimobiledevice. Instead,
uses Xcode built-in functionality.

2. Make device discovery asynchronous (#10803)
Migrates DeviceDiscovery.devices and all device-specific lookup to be
asynchronous.

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

diff --git a/packages/flutter_tools/lib/src/ios/simulators.dart b/packages/flutter_tools/lib/src/ios/simulators.dart
index 697be3b..92788c6 100644
--- a/packages/flutter_tools/lib/src/ios/simulators.dart
+++ b/packages/flutter_tools/lib/src/ios/simulators.dart
@@ -37,7 +37,7 @@
   bool get canListAnything => iosWorkflow.canListDevices;
 
   @override
-  List<Device> pollingGetDevices() => IOSSimulatorUtils.instance.getAttachedDevices();
+  Future<List<Device>> pollingGetDevices() async => IOSSimulatorUtils.instance.getAttachedDevices();
 }
 
 class IOSSimulatorUtils {