[AssetServer] Remove 'new' keyword before Promise.race()

[aleclarson]

I'm not sure if this was actually breaking anything, but I don't think new before Promise.race() is conventional.

[ghost]

By analyzing the blame information on this pull request, we identified @bestander and @davidaurelio to be potential reviewers.

[ide]

I'm confused how this was working earlier

$ node
> new Promise.race([])
TypeError: Promise.race is not a constructor

@facebook-github-bot shipit

[ghost]

Thanks for importing. If you are an FB employee go to Phabricator to review internal test results.

[facebook-github-bot]

I tried to merge this pull request into the Facebook internal repo but some checks failed. To unblock yourself please check the following: Does this pull request pass all open source tests on GitHub? If not please fix those. Does the code still apply cleanly on top of GitHub master? If not can please rebase. In all other cases this means some internal test failed, for example a part of a fb app won't work with this pull request. I've added the Import Failed label to this pull request so it is easy for someone at fb to find the pull request and check what failed. If you don't see anyone comment in a few days feel free to comment mentioning one of the core contributors to the project so they get a notification.