[REGRESSION]: Calling `browserType.launchServer` stopped working in 1.4.0

[Snikanes]

Context:

• GOOD Playwright Version: 1.3.0
• BAD Playwright Version: 1.4.0
• Operating System: RHEL 8

const chromiumServer = await chromium.launchServer({ port: 1234 });

Running the snippet above causes Error: Cannot specify a port without launching as a server to be thrown.

When calling BrowserServerLauncherImpl.launchServer with a port (which is allowed according to LaunchServerOptions) these options are immediately spread into the argument to browserType.launch. This argument is a LaunchOptions which does not accept a port. In turn, this leads the following assert to fail causing the aforementioned error.

[dgozman]

Fixed by #3877.