Support references to local extensions in codegen

compiler/testData/codegen/box/callableReference/local/extension.kt

@@ -0,0 +1,6 @@
+class A
+
+fun box(): String {
+    fun A.foo() = "OK"
+    return A().(A::foo)()
+}

compiler/testData/codegen/box/callableReference/local/extensionToLocalClass.kt

@@ -0,0 +1,5 @@
+fun box(): String {
+    class A
+    fun A.foo() = "OK"
+    return (::A)().(A::foo)()
+}

compiler/testData/codegen/box/callableReference/local/extensionToPrimitive.kt

@@ -0,0 +1,4 @@
+fun box(): String {
+    fun Int.is42With(that: Int) = this + 2 * that == 42
+    return if (16.(Int::is42With)(13)) "OK" else "Fail"
+}

compiler/testData/codegen/box/callableReference/local/extensionWithClosure.kt

@@ -0,0 +1,11 @@
+class A
+
+fun box(): String {
+    var result = "Fail"
+
+    fun A.ext() { result = "OK" }
+
+    val f = A::ext
+    A().f()
+    return result
+}