Remove never-supported JavaScript features
This PR uses the script from #6809 to remove JavaScript features that have no support in any browser.
I know that we likely have merged Temporal too early here, but are these features that will never be supported or is this an artifact of being in the progress of being implemented. If it is the latter, I'm not convinced this is a useful removal: it will come back soon(ish).
cc/ @meyerweb for more insight.
This pull request has merge conflicts that must be resolved before it can be merged.
This pull request has merge conflicts that must be resolved before it can be merged.
Given we set Safari to "preview" for Temporal now, I think we should close this.