[Tests] Migrate backend-independent tests from native to compiler/testData.

^KT-65979

compiler/testData/codegen/box/initializers/files/simpleMultiModule.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+// WITH_STDLIB
+
+// MODULE: lib
+// FILE: lib.kt
+class X(val s: String)
+
+val x = X("zzz")
+
+// MODULE: lib2(lib)
+// FILE: lib2.kt
+class Z(val x: Int)
+
+val z2 = Z(x.s.length)
+
+// MODULE: main(lib2)
+// FILE: main.kt
+import kotlin.test.*
+
+fun box(): String {
+    assertEquals(3, z2.x)
+    return "OK"
+}