Move callable reference diagnostic tests to non-stdlib

compiler/testData/diagnostics/tests/callableReference/function/nestedConstructorFromExtension.kt

@@ -0,0 +1,21 @@
+// !CHECK_TYPE
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+import kotlin.reflect.KFunction0
+
+class A {
+    class Nested
+}
+    
+fun A.main() {
+    ::<!NESTED_CLASS_SHOULD_BE_QUALIFIED!>Nested<!>
+    val y = A::Nested
+    
+    checkSubtype<KFunction0<A.Nested>>(y)
+}
+
+fun Int.main() {
+    ::<!UNRESOLVED_REFERENCE!>Nested<!>
+    val y = A::Nested
+
+    checkSubtype<KFunction0<A.Nested>>(y)
+}