chore(dev-ssr): don't dispatch CREATE_SERVER_VISITED_PAGE if component is already tracked

[pieh]

gatsby/packages/gatsby/src/bootstrap/requires-writer.ts

Lines 336 to 345 in 3ce476b

	if (process.env.GATSBY_EXPERIMENTAL_DEV_SSR) {
	/**
	* Start listening to CREATE_SERVER_VISITED_PAGE events so we can rewrite
	* files as required
	*/
	emitter.on(`CREATE_SERVER_VISITED_PAGE`, (): void => {
	reporter.pendingActivity({ id: `requires-writer` })
	debouncedWriteAll()
	})
	}

will uncodindionally run requires-writer on CREATE_SERVER_VISITED_PAGE actions. Let's skip emitting those actions that will be functionally no-ops (but still cause some extra work)

[vladar]

Thank you!

[KyleAMathews]

👍