net/http: deflake TestCancelRequestWithChannelBeforeDo_Cancel

Goroutines clean up takes longer when using deprecated CloseNotifier.

Fixes #35122

Change-Id: Id820a3012b5c781ddfb294b38ee3b009624e398c
Reviewed-on: https://go-review.googlesource.com/c/go/+/204661
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/net/http/main_test.go

@@ -122,7 +122,7 @@ func afterTest(t testing.TB) {
 		").noteClientGone(":     "a closenotifier sender",
 	}
 	var stacks string
-	for i := 0; i < 4; i++ {
+	for i := 0; i < 10; i++ {
 		bad = ""
 		stacks = strings.Join(interestingGoroutines(), "\n\n")
 		for substr, what := range badSubstring {

src/net/http/transport_test.go

@@ -22,7 +22,6 @@ import (
 	"fmt"
 	"go/token"
 	"internal/nettrace"
-	"internal/testenv"
 	"io"
 	"io/ioutil"
 	"log"
@@ -2355,9 +2354,6 @@ func TestCancelRequestWithChannel(t *testing.T) {
 }
 
 func TestCancelRequestWithChannelBeforeDo_Cancel(t *testing.T) {
-	if os.Getenv("GO_BUILDER_NAME") == "windows-amd64-longtest" {
-		testenv.SkipFlaky(t, 35122)
-	}
 	testCancelRequestWithChannelBeforeDo(t, false)
 }
 func TestCancelRequestWithChannelBeforeDo_Context(t *testing.T) {