Use captured instance in interface companion object initializer

Similar to enum entry initialization, when we have a companion object
in an interface, its constructor (or clinit) initializes its state
before the instance field in corresponding interface is initialized.
So, interface companion object must be accessed via a captured object
reference (#0, or #0.this$0 for inner anonymous objects).

compiler/testData/codegen/box/objects/interfaceCompanionObjectReference.kt

@@ -0,0 +1,37 @@
+// WITH_RUNTIME
+
+import kotlin.test.*
+
+interface Test {
+    companion object {
+        val x = "OK"
+
+        val y1 = Test.x
+
+        val y2 = 42.let { x }
+
+        val y3: String
+        init {
+            fun localFun() = x
+            y3 = localFun()
+        }
+
+        fun method() = x
+        val y4 = method()
+
+        val anonObject = object {
+            override fun toString() = x
+        }
+        val y5 = anonObject.toString()
+
+        init {
+            assertEquals(x, y1)
+            assertEquals(x, y2)
+            assertEquals(x, y3)
+            assertEquals(x, y4)
+            assertEquals(x, y5)
+        }
+    }
+}
+
+fun box() = Test.x