Migrate boxInline tests to new multi-file framework

compiler/testData/codegen/boxInline/trait/trait.2.kt

@@ -1,18 +0,0 @@
-package test
-
-interface InlineTrait {
-
-    fun finalInline(s: () -> String): String {
-        return s()
-    }
-
-    companion object {
-        inline final fun finalInline(s: () -> String): String {
-            return s()
-        }
-    }
-}
-
-class Z: InlineTrait {
-
-}

compiler/testData/codegen/boxInline/trait/trait.kt

@@ -1,3 +1,26 @@
+// FILE: 1.kt
+
+package test
+
+interface InlineTrait {
+
+    fun finalInline(s: () -> String): String {
+        return s()
+    }
+
+    companion object {
+        inline final fun finalInline(s: () -> String): String {
+            return s()
+        }
+    }
+}
+
+class Z: InlineTrait {
+
+}
+
+// FILE: 2.kt
+
 import test.*
 
 fun testFinalInline(): String {
@@ -18,4 +41,4 @@ fun box(): String {
     if (testClassObject() != "classobject") return "test3: ${testClassObject()}"
 
     return "OK"
-}
+}