8263514: Minor issue in JavacFileManager.SortFiles.REVERSE

Reviewed-by: vromero

src/jdk.compiler/share/classes/com/sun/tools/javac/file/JavacFileManager.java

@@ -123,7 +123,7 @@ public int compare(Path f1, Path f2) {
         REVERSE {
             @Override
             public int compare(Path f1, Path f2) {
-                return -f1.getFileName().compareTo(f2.getFileName());
+                return f2.getFileName().compareTo(f1.getFileName());
             }
         }
     }