[iOS] Change the min sim for watchOS. (#443)

The min simulator that can be used in xcode12.5 and later has changed.
We need to bump it.

This is a quick fix but we should be able to support the desired version
from the API.

src/Microsoft.DotNet.XHarness.iOS.Shared/Hardware/SimulatorLoader.cs

@@ -367,7 +367,7 @@ private async Task<bool> CreateDevicePair(ILog log, ISimulatorDevice device, ISi
                 TestTarget.Simulator_iOS32 => "com.apple.CoreSimulator.SimDeviceType.iPhone-5",
                 TestTarget.Simulator_iOS64 => "com.apple.CoreSimulator.SimDeviceType." + (minVersion ? "iPhone-6" : "iPhone-X"),
                 TestTarget.Simulator_tvOS => "com.apple.CoreSimulator.SimDeviceType.Apple-TV-1080p",
-                TestTarget.Simulator_watchOS => "com.apple.CoreSimulator.SimDeviceType." + (minVersion ? "Apple-Watch-38mm" : "Apple-Watch-Series-3-38mm"),
+                TestTarget.Simulator_watchOS => "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-Series-3-38mm", // min version from xcode12.5 and later.
                 _ => throw new Exception(string.Format("Invalid simulator target: {0}", target))
             };