http2: fix benchmarks using common frame read/write functions

CL 586249 unified frame read/write functions used by client
and server tests, but inadvertently broke some benchmarks.
Fix those benchmarks.

This mostly restores the previous behavior of the affected
benchmarks (for example, testing only to see that a DATA frame
contains an END_STREAM marker, ignoring the number of bytes
in the frame).

Fixes golang/go#70647

Change-Id: I2b0099c3513ac8754d11c4e37b7d63277a0fb0b1
Reviewed-on: https://go-review.googlesource.com/c/net/+/633055
Auto-Submit: Damien Neil <dneil@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Antonio Ojea <aojea@google.com>

http2/server_test.go

@@ -333,7 +333,9 @@ func newServerTesterWithRealConn(t testing.TB, handler http.HandlerFunc, opts ..
 
 // sync waits for all goroutines to idle.
 func (st *serverTester) sync() {
-	st.group.Wait()
+	if st.group != nil {
+		st.group.Wait()
+	}
 }
 
 // advance advances synthetic time by a duration.
@@ -2896,15 +2898,10 @@ func BenchmarkServerGets(b *testing.B) {
 			EndStream:     true,
 			EndHeaders:    true,
 		})
-		st.wantHeaders(wantHeader{
-			streamID:  1,
-			endStream: true,
-		})
-		st.wantData(wantData{
-			streamID:  1,
-			endStream: true,
-			size:      0,
-		})
+		st.wantFrameType(FrameHeaders)
+		if df := readFrame[*DataFrame](b, st); !df.StreamEnded() {
+			b.Fatalf("DATA didn't have END_STREAM; got %v", df)
+		}
 	}
 }
 
@@ -2939,15 +2936,10 @@ func BenchmarkServerPosts(b *testing.B) {
 			EndHeaders:    true,
 		})
 		st.writeData(id, true, nil)
-		st.wantHeaders(wantHeader{
-			streamID:  1,
-			endStream: false,
-		})
-		st.wantData(wantData{
-			streamID:  1,
-			endStream: true,
-			size:      0,
-		})
+		st.wantFrameType(FrameHeaders)
+		if df := readFrame[*DataFrame](b, st); !df.StreamEnded() {
+			b.Fatalf("DATA didn't have END_STREAM; got %v", df)
+		}
 	}
 }
 
@@ -3289,14 +3281,8 @@ func BenchmarkServer_GetRequest(b *testing.B) {
 			EndStream:     true,
 			EndHeaders:    true,
 		})
-		st.wantHeaders(wantHeader{
-			streamID:  streamID,
-			endStream: false,
-		})
-		st.wantData(wantData{
-			streamID:  streamID,
-			endStream: true,
-		})
+		st.wantFrameType(FrameHeaders)
+		st.wantFrameType(FrameData)
 	}
 }
 
@@ -3327,14 +3313,8 @@ func BenchmarkServer_PostRequest(b *testing.B) {
 			EndHeaders:    true,
 		})
 		st.writeData(streamID, true, nil)
-		st.wantHeaders(wantHeader{
-			streamID:  streamID,
-			endStream: false,
-		})
-		st.wantData(wantData{
-			streamID:  streamID,
-			endStream: true,
-		})
+		st.wantFrameType(FrameHeaders)
+		st.wantFrameType(FrameData)
 	}
 }