fix for good: case 99 / esi data pushed after processing has finished

... hopefully, finally

The previous code pushing additional data was actually working around
other bugs, which _should_ be fixed with
4f9db605 and
6b5c4e45 as shown by permutations.vtc

This should avoid running into #3109 on 6.x

src/vdp_pesi.c

@@ -892,18 +892,17 @@ vdp_pesi_bytes(struct req *req, enum vdp_action act, void **priv,
 	CHECK_OBJ_NOTNULL(node, NODE_MAGIC);
 
 	/*
-	 * special case for ESI with http_gzip_support off: gzip tail getting
-	 * pushed to us after the state engine has finished
+	 * more data getting pushed to us after ESI level 0 processing has
+	 * finished
 	 *
 	 * we would want to remove ourselves from the VDP list, but cannot, as
 	 * that would trigger our _fini while we are in _bytes - catch22...
 	 *
-	 * see e00031.vtc and e00033.vtc
 	 */
 	if (req->esi_level == 0 &&
 	    node->state >= ST_DELIVERED &&
 	    pecx->state == 99) {
-		return (VDP_bytes(req, act, ptr, len));
+		return (tree->retval);
 	}
 
 	assert(node->type == T_NEXUS);