[perl #128086] Fix precedence in hv_ename_delete

A stash’s array of names may have null for the first entry, in which
case it is not one of the effective names, and the name count will
be negative.

The ‘count > 0’ is meant to prevent hv_ename_delete from trying to
read that entry, but a precedence problem introduced in 4643eb6
stopped it from doing that.

[This commit message was written by the committer.]

hv.c

@@ -2476,9 +2476,10 @@ Perl_hv_ename_delete(pTHX_ HV *hv, const char *name, U32 len, U32 flags)
 		return;
 	    }
 	if (
-	    count > 0 && (HEK_UTF8(*namep) || (flags & SVf_UTF8)) 
+	    count > 0 && ((HEK_UTF8(*namep) || (flags & SVf_UTF8)) 
                 ? hek_eq_pvn_flags(aTHX_ *namep, name, (I32)len, flags)
 	        : (HEK_LEN(*namep) == (I32)len && memEQ(HEK_KEY(*namep), name, len))
+            )
 	) {
 	    aux->xhv_name_count = -count;
 	}