net/http: enable timeout tests on Plan 9

Deadlines have been implemented on Plan 9 in CL 31521.

Enable the following tests:

 - TestServerTimeouts
 - TestOnlyWriteTimeout
 - TestTLSHandshakeTimeout
 - TestIssue4191_InfiniteGetTimeout
 - TestIssue4191_InfiniteGetToPutTimeout

Updates #7237.

Change-Id: If5e75cfaa9133dcf9ce6aac9fc2badafc1612b64
Reviewed-on: https://go-review.googlesource.com/33197
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/net/http/serve_test.go

@@ -461,9 +461,6 @@ func TestMuxRedirectLeadingSlashes(t *testing.T) {
 }
 
 func TestServerTimeouts(t *testing.T) {
-	if runtime.GOOS == "plan9" {
-		t.Skip("skipping test; see https://golang.org/issue/7237")
-	}
 	setParallel(t)
 	defer afterTest(t)
 	reqNum := 0
@@ -542,9 +539,6 @@ func TestServerTimeouts(t *testing.T) {
 // request) that will never happen.
 func TestOnlyWriteTimeout(t *testing.T) {
 	setParallel(t)
-	if runtime.GOOS == "plan9" {
-		t.Skip("skipping test; see https://golang.org/issue/7237")
-	}
 	defer afterTest(t)
 	var conn net.Conn
 	var afterTimeoutErrc = make(chan error, 1)
@@ -1035,9 +1029,6 @@ func testHeadResponses(t *testing.T, h2 bool) {
 }
 
 func TestTLSHandshakeTimeout(t *testing.T) {
-	if runtime.GOOS == "plan9" {
-		t.Skip("skipping test; see https://golang.org/issue/7237")
-	}
 	setParallel(t)
 	defer afterTest(t)
 	ts := httptest.NewUnstartedServer(HandlerFunc(func(w ResponseWriter, r *Request) {}))

src/net/http/transport_test.go

@@ -1352,9 +1352,6 @@ func TestTransportConcurrency(t *testing.T) {
 
 func TestIssue4191_InfiniteGetTimeout(t *testing.T) {
 	setParallel(t)
-	if runtime.GOOS == "plan9" {
-		t.Skip("skipping test; see https://golang.org/issue/7237")
-	}
 	defer afterTest(t)
 	const debug = false
 	mux := NewServeMux()
@@ -1417,9 +1414,6 @@ func TestIssue4191_InfiniteGetTimeout(t *testing.T) {
 
 func TestIssue4191_InfiniteGetToPutTimeout(t *testing.T) {
 	setParallel(t)
-	if runtime.GOOS == "plan9" {
-		t.Skip("skipping test; see https://golang.org/issue/7237")
-	}
 	defer afterTest(t)
 	const debug = false
 	mux := NewServeMux()