Try to resolve graphql schema loading race conditions in Jest

Summary:
I keep running into Jest race conditions that seem related to loading the schema.graphql file. I haven't really figured out what's going on, it just appears that the Apollo cache is somehow being written with certain fields missing.

This is a bit of a shot in the dark, as I haven't seen any GH issues that quite match what I'm seeing here.

Test Plan: Jest

Reviewers: bengotow, sashank

Reviewed By: sashank

Differential Revision: https://dagster.phacility.com/D5227