[Glimmer 2] Port partial tests

[chadhietala]

This supersedes #13199

[chadhietala]

@chancancode @wycats r+?

[chancancode]

✔️ should render other templates registered with the container

[chancancode]

@chadhietala looks great to me other than two missing assertions!

As a follow-up to this (you can send it as a separate PR if you prefer), can you add some tests to confirm whether we support accessing the "local variables" in the current scope inside a partial?

e.g. {{#with foo as |bar|}}{{partial "triesToUseBarInThePartial}}{{/with}} or {{#each foo as |bar|}}{{partial "triesToUseBarInThePartial}}{{/with}}

[chadhietala]

@chancancode Can you kick the sauce labs? Seems to have failed for unrelated reasons?

[chancancode]

🏃 kicked

[chancancode]

Thank you @chadhietala and @jheth!!