Revert "[asm-cherry-pick] expose Label.flags"

This reverts commit 5207e51.

Author: retronym

src/main/java/scala/tools/asm/Label.java

@@ -142,7 +142,7 @@ public class Label {
    * #FLAG_REACHABLE}, {@link #FLAG_SUBROUTINE_CALLER}, {@link #FLAG_SUBROUTINE_START}, {@link
    * #FLAG_SUBROUTINE_END}.
    */
-  public int flags;
+  short flags;
 
   /**
    * The source line number corresponding to this label, or 0. If there are several source line