Migrate boxWithJava tests to multi-file framework

compiler/testData/codegen/boxWithJava/statics/protectedSamConstructor.kt

@@ -0,0 +1,27 @@
+// FILE: JavaClass.java
+
+public class JavaClass {
+
+    public String runZ(Z z) {
+        return z.run("O", "K");
+    }
+
+    protected interface Z {
+        String run(String s1, String s2);
+    }
+}
+
+// FILE: Kotlin.kt
+
+package zzz
+
+import JavaClass
+import JavaClass.Z
+
+class A : JavaClass() {
+    fun test() = runZ(JavaClass.Z {a, b -> a + b})
+}
+
+fun box(): String {
+    return A().test()
+}