os: skip TestNetworkSymbolicLink if Server service is not started

Fixes #20179

Change-Id: I2b405c9a212a75aae628ad51885616d33c054191
Reviewed-on: https://go-review.googlesource.com/42190Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/os/os_windows_test.go

@@ -429,6 +429,8 @@ func TestDirectorySymbolicLink(t *testing.T) {
 func TestNetworkSymbolicLink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
+	const _NERR_ServerNotStarted = syscall.Errno(2114)
+
 	dir, err := ioutil.TempDir("", "TestNetworkSymbolicLink")
 	if err != nil {
 		t.Fatal(err)
@@ -479,6 +481,9 @@ func TestNetworkSymbolicLink(t *testing.T) {
 		if err == syscall.ERROR_ACCESS_DENIED {
 			t.Skip("you don't have enough privileges to add network share")
 		}
+		if err == _NERR_ServerNotStarted {
+			t.Skip(_NERR_ServerNotStarted.Error())
+		}
 		t.Fatal(err)
 	}
 	defer func() {