TEST: companion and init0 tests

(cherry picked from commit f8e80249e9f986ae58a52a57173d2cb0b68a653b)

backend.native/tests/codegen/basics/companion.kt

@@ -0,0 +1,5 @@
+class A {
+  companion object {
+    fun foo() = "comp"
+  }
+}

backend.native/tests/codegen/object/init0.kt

@@ -0,0 +1,6 @@
+class A(a:Int) {
+  var i:Int = 0
+  init {
+    if (a == 0) i = 1
+  }
+}