Support "::foo" as a short-hand for "this::foo"

#KT-15667 Fixed

compiler/testData/codegen/box/callableReference/bound/emptyLHS.kt

@@ -0,0 +1,58 @@
+// IGNORE_BACKEND: JS
+// LANGUAGE_VERSION: 1.2
+
+var result = ""
+
+class A {
+    fun memberFunction() { result += "A.mf," }
+    fun aMemberFunction() { result += "A.amf," }
+    val memberProperty: Int get() = 42.also { result += "A.mp," }
+    val aMemberProperty: Int get() = 42.also { result += "A.amp," }
+
+    fun test(): String {
+        (::memberFunction)()
+        (::aExtensionFunction)()
+
+        (::memberProperty)()
+        (::aExtensionProperty)()
+
+        return result
+    }
+
+    inner class B {
+        fun memberFunction() { result += "B.mf," }
+        val memberProperty: Int get() = 42.also { result += "B.mp," }
+
+        fun test(): String {
+            (::aMemberFunction)()
+            (::aExtensionFunction)()
+
+            (::aMemberProperty)()
+            (::aExtensionProperty)()
+
+            (::memberFunction)()
+            (::memberProperty)()
+
+            (::bExtensionFunction)()
+            (::bExtensionProperty)()
+
+            return result
+        }
+    }
+}
+
+fun A.aExtensionFunction() { result += "A.ef," }
+val A.aExtensionProperty: Int get() = 42.also { result += "A.ep," }
+fun A.B.bExtensionFunction() { result += "B.ef," }
+val A.B.bExtensionProperty: Int get() = 42.also { result += "B.ep," }
+
+fun box(): String {
+    val a = A().test()
+    if (a != "A.mf,A.ef,A.mp,A.ep,") return "Fail $a"
+
+    result = ""
+    val b = A().B().test()
+    if (b != "A.amf,A.ef,A.amp,A.ep,B.mf,B.mp,B.ef,B.ep,") return "Fail $b"
+
+    return "OK"
+}