REGTESTS: adjust the http-rules regtest to support window updates

Varnishtest is not happy to see the window update come before the
settings ACK, as by default it expects exactly tx/rx/txack/rxack.
One workaround could consist in making haproxy send the WU after
the settings ACK but this would be a real hack as the preface is
already finished when sending this ack. Instead, let's make the
initial sequence explicit in the tests.
diff --git a/reg-tests/http-rules/h00001.vtc b/reg-tests/http-rules/h00001.vtc
index ca86f1b..2056ea7 100644
--- a/reg-tests/http-rules/h00001.vtc
+++ b/reg-tests/http-rules/h00001.vtc
@@ -187,6 +187,15 @@
 } -run
 
 client c1h2 -connect ${h1_feh2_sock} {
+	txpri
+	stream 0 {
+		txsettings
+		rxsettings
+		txsettings -ack
+		rxwinup
+		rxsettings
+		expect settings.ack == true
+	} -run
 	stream 1 {
 		# warning: -req, -scheme, -url MUST be placed first otherwise
 		# the H2 protocol is invalid since they are pseudo-headers
diff --git a/reg-tests/http-rules/h00002.vtc b/reg-tests/http-rules/h00002.vtc
index b1a6b7b..1f3c29d 100644
--- a/reg-tests/http-rules/h00002.vtc
+++ b/reg-tests/http-rules/h00002.vtc
@@ -188,6 +188,15 @@
 } -run
 
 client c1h2 -connect ${h1_feh2_sock} {
+	txpri
+	stream 0 {
+		txsettings
+		rxsettings
+		txsettings -ack
+		rxwinup
+		rxsettings
+		expect settings.ack == true
+	} -run
 	stream 1 {
 		# warning: -req, -scheme, -url MUST be placed first otherwise
 		# the H2 protocol is invalid since they are pseudo-headers