Adds two tests covering the fix in 0e4c8fc92:
TestDialNodeUsingProxyPort exercises dialNodeUsingProxy directly via a
stub CONNECT proxy, asserting the recorded target across four cases:
HTTPS/HTTP default fallback and explicit DERPPort override for each.
TestConnectThroughProxyHonorsDERPPort drives the full path end-to-end:
a real derpserver on an ephemeral TLS port, a real CONNECT proxy that
tunnels bytes bidirectionally, and a region client routed through it
via feature.HookProxyFromEnvironment. Without the fix, Connect fails
because the proxy is asked to dial :443.
Signed-off-by: Martin Zihlmann <martizih@outlook.com>
Martin ZihlmannandBrad Fitzpatrick
48eba4e971