Migrate boxWithJava tests to multi-file framework

compiler/testData/codegen/boxWithJava/properties/collectionSize.kt

@@ -0,0 +1,21 @@
+// FILE: Test.java
+
+public class Test extends java.util.ArrayList<String> {
+    public final int size() {
+        return 56;
+    }
+}
+
+// FILE: test.kt
+
+class OurTest : Test()
+
+fun box(): String {
+    val t = OurTest()
+    val x: MutableCollection<String> = t
+
+    if (t.size != 56) return "fail 1: ${t.size}"
+    if (x.size != 56) return "fail 1: ${x.size}"
+
+    return "OK"
+}