[K/N][Tests] Migrate framework and objcexport tests

^KT-61259

native/native.tests/testData/framework/objcexport/headerWarnings.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+package headerWarnings
+
+// Note: the test parses the generated header with -Werror to detect warnings.
+
+class TestIncompatiblePropertyTypeWarning {
+    class Generic<T>(val value: T)
+
+    interface InterfaceWithGenericProperty<T> {
+        val p: Generic<T>
+    }
+
+    class ClassOverridingInterfaceWithGenericProperty(override val p: Generic<String>) : InterfaceWithGenericProperty<String>
+}
+
+// https://github.com/JetBrains/kotlin-native/issues/3992
+class TestGH3992 {
+    abstract class C(open val a: A)
+
+    class D(override val a: B) : C(a)
+
+    abstract class A
+
+    class B : A()
+}