Fix completion for private_to_this.

idea/testData/completion/basic/common/visibility/VisibilityInSubclass.kt

@@ -0,0 +1,16 @@
+class Some() {
+    public val testPublic = 12
+    protected val testProtected = 12
+    private val testPrivate = 12
+    val testPackage = 12
+}
+
+class SomeSubclass : Some() {
+    fun test() {
+        <caret>
+    }
+}
+
+// INVOCATION_COUNT: 1
+// EXIST: testPublic, testProtected, testPackage
+// ABSENT: testPrivate