Unmounting one of multiple components that share a duplicate query deletes RecordSource records

If you include two `QueryRenderer`s on a page that have the same query, and then you remove one, it deletes the store data associated with the component because `fetchQueryAndComputeStateFromProps` in `ReactRelayQueryRenderer.jsx` doesn't properly handle duplicate requests from different components.

When `fetchQueryAndComputeStateFromProps` is called the first time, it calls `fetch` in `ReactRelayQueryFetcher`, which then calls `execute`. After the environment executes, eventually `environment.retain` is called in `ReactRelayQueryFetcher.execute`, which retains the returned data in the `RelayMarkSweepStore` (assuming you are using the normal store setup). The second time `fetchQueryAndComputeStateFromProps` is called it does not call `execute` because the query matches an in-flight request. Therefore, the data is not retained a second time in the `RelayMarkSweepStore`. When you unmount either component, it `dispose`s the selector in `RelayMarkSweepStore`, which performs a `gc`, deleting the data for all remaining components.

I attempted to create a repro of this, but the glitch site linked in the Issues description is extremely out of date and doesn't support Relay Modern. The above was determined using Relay 1.7.0.