Migrate boxAgainstJava tests to multi-file framework

compiler/testData/codegen/boxAgainstJava/sam/adapters/inheritedInKotlin.kt

@@ -1,3 +1,13 @@
+// FILE: JavaClass.java
+
+class JavaClass {
+    public void run(Runnable r) {
+        r.run();
+    }
+}
+
+// FILE: 1.kt
+
 internal class KotlinSubclass: JavaClass() {
 }
 
@@ -5,4 +15,4 @@ fun box(): String {
     var v = "FAIL"
     KotlinSubclass().run { v = "OK" }
     return v
-}
+}