Postpone companion object field visibility

Have to reconsider this issue because of interface companion objects.

compiler/testData/codegen/box/objects/companionObjectAccess/kt27117_lv13.kt

@@ -0,0 +1,16 @@
+// LANGUAGE_VERSION: 1.3
+
+inline fun on(body: () -> Any) = body().toString()
+
+class A {
+    fun test() = foo()
+
+    private companion object {
+        private fun foo() = on { this }
+
+        override fun toString() = "OK"
+    }
+}
+
+
+fun box() = A().test()