Make split stronger, resp. behave like the coq split

hol/Infra/tactics.hl

@@ -39,7 +39,9 @@ let lcontra asm ty = lcontradiction asm ty;;
 let destruct (asm:string) (patt:string) =
   REMOVE_THEN asm (DESTRUCT_TAC patt);;
 
-let split = CONJ_TAC;;
+let split = if (is_conj (snd (top_goal()))) then  CONJ_TAC
+else if (is_eq (snd (top_goal()))) then EQ_TAC
+else failwith "No destructable equivalence found";;
 
 let left = DISJ1_TAC;;
 let right = DISJ2_TAC;;