[IR][tests] Add tests for removal-of-overridden open callable case

compiler/testData/klibABI/removeOpenFunction/main/m.kt

@@ -0,0 +1,3 @@
+fun box(): String {
+    return C2().foo() + I2().foo()
+}

compiler/testData/klibABI/removeOpenFunction/main/module.info

@@ -0,0 +1,2 @@
+STEP 0:
+    dependencies: stdlib, lib1, lib2