Migrate boxAgainstJava tests to multi-file framework

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

@@ -1,3 +1,19 @@
+// FILE: JavaClass.java
+
+class JavaClass {
+    private Runnable r;
+
+    public JavaClass(Runnable r) {
+        this.r = r;
+    }
+
+    public void run() {
+        r.run();
+    }
+}
+
+// FILE: 1.kt
+
 var status: String = "fail"  // global property to avoid issues with accessing closure from local class (KT-4174)
 
 fun box(): String {
@@ -5,4 +21,3 @@ fun box(): String {
     C().run()
     return status
 }
-