Fix unregister order of inheritance chains

Sources/SwiftGodotTestability/GodotTestCase.swift

@@ -25,7 +25,7 @@ open class GodotTestCase: EmbeddedTestCase<GodotTestHost> {
     override open class func tearDown() {
         if GodotRuntime.isRunning {
             // unregister any types that were registered for the tests
-            for subclass in godotSubclasses {
+            for subclass in godotSubclasses.reversed() {
                 unregister(type: subclass)
             }
         }