Add an HTTP/2 test to e31.vtc.

src/tests/e00031.vtc

@@ -25,3 +25,19 @@ client c1 {
 	gunzip
 	expect resp.body == "bar"
 } -run
+
+## HTTP/2
+
+varnish v1 -cliok "param.set feature +http2"
+
+## See comments in e23.vtc about limitations using vtc to test
+## gzipped H2 responses.
+
+client c1 {
+	stream 1 {
+		txreq
+		rxresp
+		expect resp.http.content-encoding == gzip
+		expect resp.status == 200
+	} -run
+} -run