Revert "Temporary: comment the last check in JavaUsageTest (KT-66551)"

This reverts commit f2ec6d7495.

libraries/kotlinx-metadata/jvm/test/kotlin/metadata/test/JavaUsageTest.java

@@ -34,6 +34,6 @@ public class JavaUsageTest {
         Metadata written = clazz1.write();
         //noinspection KotlinInternalInJava
         assertArrayEquals(written.mv(), JvmMetadataVersion.LATEST_STABLE_SUPPORTED.toIntArray());
-        //assertEquals(50, written.xi());
+        assertEquals(50, written.xi());
     }
 }