wasm: add test for disallowed JS/WASM dependencies

Ensures that binary size gains like the ones from #4802 and #4813
don't regress.

Updates #3517

Signed-off-by: Mihai Parparita <mihai@tailscale.com>

tstest/jsdeps/jsdeps.go

@@ -0,0 +1,36 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package jsdeps is a just a list of the packages we import in the
+// JavaScript/WASM build, to let us test that our transitive closure of
+// dependencies on iOS doesn't accidentally grow too large, since binary size
+// is more of a concern there.
+package jsdeps
+
+import (
+	_ "bytes"
+	_ "context"
+	_ "encoding/hex"
+	_ "encoding/json"
+	_ "fmt"
+	_ "log"
+	_ "math/rand"
+	_ "net"
+	_ "strings"
+	_ "time"
+
+	_ "golang.org/x/crypto/ssh"
+	_ "inet.af/netaddr"
+	_ "tailscale.com/control/controlclient"
+	_ "tailscale.com/ipn"
+	_ "tailscale.com/ipn/ipnserver"
+	_ "tailscale.com/net/netns"
+	_ "tailscale.com/net/tsdial"
+	_ "tailscale.com/safesocket"
+	_ "tailscale.com/tailcfg"
+	_ "tailscale.com/types/logger"
+	_ "tailscale.com/wgengine"
+	_ "tailscale.com/wgengine/netstack"
+	_ "tailscale.com/words"
+)