[xharness] Don't run the mono-native-compat test on ARM64_32.

ARM64_32 only supports the unified native mode.

tests/xharness/Harness.cs

@@ -364,7 +364,8 @@ namespace xharness
 				var monoNativeInfo = new MonoNativeInfo (this, flavor);
 				var iosTestProject = new iOSTestProject (monoNativeInfo.ProjectPath, generateVariations: false) {
 					MonoNativeInfo = monoNativeInfo,
-					Name = monoNativeInfo.ProjectName
+					Name = monoNativeInfo.ProjectName,
+					SkipwatchOSARM64_32Variation = monoNativeInfo.ProjectName.Contains ("compat"),
 				};
 
 				IOSTestProjects.Add (iosTestProject);

tests/xharness/Jenkins.cs

@@ -606,6 +606,7 @@ namespace xharness
 					buildWatch32.CloneTestProject (watchOSProject);
 					rv.Add (new RunDeviceTask (buildWatch32, Devices.ConnectedWatch) { Ignored = ignored || !IncludewatchOS, BuildOnly = project.BuildOnly });
 
+					if (!project.SkipwatchOSARM64_32Variation) {
 						var buildWatch64_32 = new XBuildTask {
 							Jenkins = this,
 							ProjectConfiguration = "Debug64_32",
@@ -618,6 +619,7 @@ namespace xharness
 						rv.Add (new RunDeviceTask (buildWatch64_32, Devices.ConnectedWatch32_64.Where (d => d.IsSupported (project))) { Ignored = ignored || !IncludewatchOS, BuildOnly = project.BuildOnly });
 					}
 				}
+			}
 
 			return CreateTestVariations (rv, (buildTask, test, candidates) => new RunDeviceTask (buildTask, candidates?.Cast<Device> () ?? test.Candidates));
 		}

tests/xharness/TestProject.cs

@@ -150,6 +150,7 @@ namespace xharness
 	{
 		public bool SkipiOSVariation;
 		public bool SkipwatchOSVariation;
+		public bool SkipwatchOSARM64_32Variation;
 		public bool SkiptvOSVariation;
 		public bool BuildOnly;