Add lints to guest programs

[jonathanpwang]

The crates for guest programs used in benchmarks and integration tests are not part of the Cargo workspace, which is intentional since the guest programs are designed to target RISC-V. These guest programs are usually in a **/benchmarks/programs or **/test/programs folders.

We should add a lint workflow step to run cargo fmt and cargo clippy on these crates, making sure to lint for all targets.