Add test support for types and objects creation

* test_support::TypeInfoHolder to create TypeInfo given payload description
* test_support::Object<Payload> to create objects with Payload and to get them from ObjHeader* after checking that their type_info are layout compatible.
* test_support::*Array<Count> to create various arrays with given length and similarly get them from ArrayHeader*.

kotlin-native/runtime/src/mm/cpp/Memory.cpp

@@ -116,6 +116,11 @@ extern "C" void RestoreMemory(MemoryState*) {
     // TODO: Remove when legacy MM is gone.
 }
 
+extern "C" void ClearMemoryForTests(MemoryState* state) {
+    auto* threadData = FromMemoryState(state)->Get();
+    threadData->ClearForTests();
+}
+
 extern "C" RUNTIME_NOTHROW OBJ_GETTER(AllocInstance, const TypeInfo* typeInfo) {
     auto* threadData = mm::ThreadRegistry::Instance().CurrentThreadData();
     RETURN_RESULT_OF(mm::AllocateObject, threadData, typeInfo);