Handle unbound extension receiver in callable reference adaptation

compiler/testData/ir/irText/expressions/callableReferences/adaptedExtensionFunctions.kt

@@ -0,0 +1,23 @@
+// !LANGUAGE: +NewInference +FunctionReferenceWithDefaultValueAsOtherType
+
+fun use(f: C.(Int) -> Unit) {}
+
+class C
+
+fun C.extensionVararg(i: Int, vararg s: String) {}
+
+fun C.extensionDefault(i: Int, s: String = "") {}
+
+fun C.extensionBoth(i: Int, s: String = "", vararg t: String) {}
+
+fun testExtensionVararg() {
+    use(C::extensionVararg)
+}
+
+fun testExtensionDefault() {
+    use(C::extensionDefault)
+}
+
+fun testExtensionBoth() {
+    use(C::extensionBoth)
+}