Add a timeout when testing for a local test server.
Add a timeout when testing for a local test server.

For some bizarre reason my machine can't ping itself, and request
was falling back to its default timeout, which is like 90 seconds or
something. Which is crazy. The server's running locally, so if we
can't reach it within 500ms, it seems safe to assume it's dead.

fbshipit-source-id: d480bc4

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