[Test] Move KotlinAgainstKotlin tests under BlackBoxCodegen tests

compiler/testData/codegen/box/compileKotlinAgainstKotlin/importCompanion.kt

@@ -0,0 +1,19 @@
+// WITH_RUNTIME
+// TARGET_BACKEND: JVM
+
+// MODULE: lib
+// FILE: 1.kt
+package test
+
+class C(val x: String) {
+    companion object {
+        @JvmField
+        val instance: C = C("OK")
+    }
+}
+
+// MODULE: main(lib)
+// FILE: 2.kt
+import test.C.Companion.instance
+
+fun box() = instance.x