[monotouch-test] Fix BlocksTest to work on maccatalyst-arm64. (#18708)

We use the AOT compiler on ARM64 on Mac Catalyst, so these tests have to
be excluded on Mac Catalyst.

tests/monotouch-test/ObjCRuntime/BlocksTest.cs

@@ -72,7 +72,7 @@ namespace MonoTouchFixtures.ObjCRuntime {
 			}
 		}
 
-#if !DEVICE && !MONOMAC && !AOT // some of these tests cause the AOT compiler to assert
+#if !DEVICE && !MONOMAC && !AOT && !__MACCATALYST__ // some of these tests cause the AOT compiler to assert
 		// No MonoPInvokeCallback
 		static void InvalidTrampoline1 () { }