Summary: Right now, if you are changing something in one of the modules, e.g. in "flipper-plugin", you'll need to compile the changed module using `tsc` before running tests, otherwise `jest` won't pick up the changes. `yarn test` has a step to run `tsc` before tests, however when tests are started simply by `jest` command, e.g. by VSCode plugin, then `tsc` is not automatically called before tests. This diff makes things easier by configuring `jest` to automatically transpile imported modules. This means simply running `jest` command will automatically pick up and automatically transpile all the changes.
Reviewed By: passy
Differential Revision: D28310318
fbshipit-source-id: 77e9b91daa59a46ce64b1b70eb9a998d7b72de00
