`ggez` crate fails to build with OOM

[icefoxen]

(Loose summary of conversation on the #crater Discord.)

I maintain a crate, ggez, that fails to build on crater with OOM. Example. Turns out that this is because the crate has lots of examples, and it has lots of dependencies so linking each example consumes about 500 MB of memory at a time. Just doing cargo test tries to build a bunch of the examples at once, and hits Crater's 1.5 GB memory limit. Doing it with -j 1 however should be able to build them successfully. It was suggested that running all crater jobs with -j 1 might be feasible, since overall throughput would stay the same.

This is purely a nice-to-have for me, so as far as I'm concerned it's entirely up to you guys to decide if/how to solve this. Thank you!