* Use core-js promise polyfill for nomodule browsers
Also updated to the core-js@3 features modules instead of importing the exact modules directly.
Fixes#10966
* Simplify reflect and regexp
* Add ie11 test for bad Promise
* Add test script for regexp and ie11
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Joe Haddad <joe.haddad@zeit.co>
* Match public files priority in dev
* Remove un-needed old public file handling
* Run public file priority test for non-dev also
* Make sure to enable publicDirectory
* Add checking for conflicting pages in dev and during build
* Add error for public dir middleware conflict
* Add err.sh for _next conflict
* Move up public dir conflict checking
* Only run _next conflict check in dev when path contains it