Summary:
Renamed test files to match `-test.js`, so people can add test helpers without blacklisting.
Codemod code: P60365841
Script executed:
```
cd xplat/js
./scripts/node/node rename-script.js > result.txt
```
Reviewed By: mjesun
Differential Revision: D13185673
fbshipit-source-id: 87451635aa538c2c1d1886e75574d0e5c889596e