Use common instance receiver generation logic for 'this' expression

Otherwise it would skip private companion object accessor generation.

compiler/testData/codegen/box/objects/companionObjectAccess/kt27117.kt

@@ -0,0 +1,17 @@
+// !LANGUAGE: +ProperVisibilityForCompanionObjectInstanceField
+// IGNORE_BACKEND: JS, JS_IR, JVM_IR
+
+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()