ci: add support for loongarch64-unknown-linux-{gnu,musl}

[heiher]

No description provided.

[briansmith]

Thanks. I don't want to add these to the CI matrix because they are just going to be running the same code that is already tested in other targets and the matrix is already too huge. However, I would like to accept the changes to cargo.sh and install-build-tools.sh. Could you revert the changes to ci.yml and leave the rest? Thanks!

[briansmith]

There is no assembly in our code for these targets.

[heiher]

Thanks. I don't want to add these to the CI matrix because they are just going to be running the same code that is already tested in other targets and the matrix is already too huge. However, I would like to accept the changes to cargo.sh and install-build-tools.sh. Could you revert the changes to ci.yml and leave the rest? Thanks!

Thanks for your review. It's done.