[zeit/next.js] Pre-release v9.3.1-canary.2 - v9.3.1-canary.2

DRANK

### Patches - Make sure to not show pages/404 GIP error from _app having GIP: #10974 - Fix examples with relay-compiler: #10976 - Use core-js promise polyfill for nomodule browsers: #10985 - Improve Sass Error: #10982 - Add support for getStaticProps in pages/404: #10984 ### Credits Huge thanks to @ijjk, @messa, and @timneutkens for helping!