crypto/tls: include close notify in client tls test recordings

This commit fixes the issue where tls testdata recordings made with the
newer version of the prerecorded tls conversation test harness, doesn't
end up capturing the final close notify message. The fix simply ensures
that the tls.Client closes before the recording of the conversation is
closed. The closing of the client connection directly is no longer
needed when updating the recording since it will be closed when the
tls.Client is closed.

Fixes golang/go#69846

Change-Id: I93898de32abd89659a32ed240df6daea5aeaa7fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/620395
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Auto-Submit: Filippo Valsorda <filippo@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

src/crypto/tls/handshake_client_test.go

@@ -433,7 +433,7 @@ func (test *clientTest) run(t *testing.T, write bool) {
 	}
 
 	if write {
-		clientConn.Close()
+		client.Close()
 		path := test.dataPath()
 		out, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
 		if err != nil {