squashme: r03996: implement dridi-barriers

Author: daghf

bin/varnishtest/tests/r03996.vtc

@@ -1,6 +1,6 @@
 varnishtest "h2 rapid reset"
 
-barrier b1 sock 2 -cyclic
+barrier b1 sock 5
 
 server s1 {
 	rxreq
@@ -30,24 +30,21 @@ client c1 {
 	stream 1 {
 		txreq
 		txrst
-		barrier b1 sync
 	} -run
 	stream 3 {
 		txreq
 		txrst
-		barrier b1 sync
 	} -run
 	stream 5 {
 		txreq
 		txrst
-		barrier b1 sync
 	} -run
 	stream 7 {
 		txreq
 		txrst
-		barrier b1 sync
 	} -run
 
+	barrier b1 sync
 	stream 0 -wait
 } -run