Migrate boxAgainstJava tests to multi-file framework

compiler/testData/codegen/boxAgainstJava/sam/kt4753_2.kt

@@ -1,3 +1,20 @@
+// FILE: ParamBase.java
+
+class ParamBase<T> {}
+
+// FILE: F.java
+
+interface F<T> extends FBase<ParamBase<? extends T>> {
+}
+
+// FILE: FBase.java
+
+interface FBase<T> {
+    void call(T t);
+}
+
+// FILE: 1.kt
+
 fun box(): String {
     F<ParamBase<Int>>({}).call(ParamBase())
     return "OK"