Allow user to specify ICEs to run + add two new ones

[BGR360]

Was just going to add the two new ICEs, but some of the existing ICEs take an extraordinary amount of time to run on my machine.

So I just added the ability to optionally filter down to one or more specific ICEs when doing cargo run.

cc rust-lang/rust#101696 for the two new ICEs

[Alexendoo]

Nice thanks, will take a look in a moment

Do you know which ones were taking ages on your machine? We try not to have ones that take an inordinate amount of time

[matthiaskrgr]

Are they related to save analysis? rust-lang/rust#101505

[BGR360]

I don't know how to tell which ones were taking long. They only show up as .... in the terminal

[matthiaskrgr]

Hmm, on my machine a cargo run finishes within 42 seconds.
if we hadn't named all the outputs in the rustdoc tests "out.rs" we could tell what file was being checked via ps -aux :/

[BGR360]

I'm running on an M1 Pro macbook if that makes any difference 🤷

I'll stick some debug logs in there to figure out which ones are running slow

[JohnTitor]

I guess the below is clearer:

Suggested change

	`cargo run NUMBER` to run your ICE.
	`cargo run $ISSUE_NUMBER` to run your ICE.

[JohnTitor]

LGTM! I think we can merge once the comment above is resolved and 09ccc5c is dropped.