cmd/testwrapper: move from corp; mark magicsock test as flaky

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ibab5860f5797b3db151d3c27855333e43a9088a4

wgengine/magicsock/magicsock_test.go

@@ -32,6 +32,7 @@ import (
 	"github.com/tailscale/wireguard-go/tun/tuntest"
 	"go4.org/mem"
 	"golang.org/x/exp/maps"
+	"tailscale.com/cmd/testwrapper/flakytest"
 	"tailscale.com/derp"
 	"tailscale.com/derp/derphttp"
 	"tailscale.com/disco"
@@ -602,6 +603,7 @@ func (localhostListener) ListenPacket(ctx context.Context, network, address stri
 }
 
 func TestTwoDevicePing(t *testing.T) {
+	flakytest.Mark(t, "https://github.com/tailscale/tailscale/issues/1277")
 	l, ip := localhostListener{}, netaddr.IPv4(127, 0, 0, 1)
 	n := &devices{
 		m1:     l,