Add labels for extension properties

#KT-2824 Fixed

compiler/testData/resolve/labels/labelForPropertyInGetter.jet

@@ -0,0 +1,47 @@
+trait Base {
+    fun foo()
+}
+
+val ~getter1~Int.getter1: Int
+    get() {
+        return `getter1`this@getter1
+    }
+
+val ~getter2~Int.getter2: Base
+    get() {
+        return object: Base {
+            override fun foo() {
+                `getter2`this@getter2
+            }
+        }
+    }
+
+val ~getter3~Int.getter3: Base
+    get() = object: Base {
+        override fun foo() {
+            `getter3`this@getter3
+        }
+    }
+
+val ~getter4~Int.getter4: Int
+    get() {
+        return {
+            `getter4`this@getter4
+        }.invoke()
+    }
+
+val ~getter5~Int.getter5: Int
+    get() {
+        val extFun = { Int.() ->
+            `getter5`this@getter5
+        }
+        return `getter5`this@getter5.extFun()
+    }
+
+
+class Test {
+    val ~innerGetter1~Int.innerGetter1: Int
+        get() {
+            return `innerGetter1`this@innerGetter1
+        }
+}

compiler/testData/resolve/labels/labelForPropertyInSetter.jet

@@ -0,0 +1,32 @@
+trait Base {
+    fun foo()
+}
+
+var ~setter1~Int.setter1: Int = 2
+    set(i: Int) {
+        $setter1 = `setter1`this@setter1
+    }
+
+var ~setter2~Int.setter2: Base? = null
+    set(i: Base?) {
+        $setter2 = object: Base {
+            override fun foo() {
+                `setter2`this@setter2
+            }
+        }
+    }
+
+var ~setter3~Int.setter3: Int = 1
+    set(i: Int) {
+        {
+            `setter3`this@setter3
+        }.invoke()
+    }
+
+var ~setter4~Int.setter4: Int = 1
+    set(i: Int) {
+        val extFun = { Int.() ->
+            `setter4`this@setter4
+        }
+        `setter4`this@setter4.extFun()
+    }