Report diagnostic on overrides of experimental members

Unless they're experimental themselves

 #KT-22759 In Progress

compiler/testData/diagnostics/testsWithStdLib/experimental/overrideDifferentExperimentalities.kt

@@ -0,0 +1,35 @@
+// !API_VERSION: 1.3
+
+@Experimental(Experimental.Level.WARNING)
+annotation class E1
+@Experimental(Experimental.Level.WARNING)
+annotation class E3
+
+interface Base1 {
+    @E1
+    fun foo()
+}
+
+interface Base2 {
+    fun foo()
+}
+
+interface Base3 {
+    @E3
+    fun foo()
+}
+
+class DerivedA : Base1, Base2, Base3 {
+    override fun <!EXPERIMENTAL_OVERRIDE, EXPERIMENTAL_OVERRIDE!>foo<!>() {}
+}
+
+class DerivedB : Base1, Base3 {
+    @E3
+    override fun <!EXPERIMENTAL_OVERRIDE!>foo<!>() {}
+}
+
+class DerivedC : Base1, Base2, Base3 {
+    @E1
+    @E3
+    override fun foo() {}
+}