ci: test AArch64 Linux and run tests instead of build in cross job

[taiki-e]

Motivation

Currently, "cross" job in our CI is build-only and doesn't run tests:

bytes/.github/workflows/ci.yml

Lines 121 to 129 in 3ab876f

	- name: cross build --target ${{ matrix.target }}
	run: cross build --target ${{ matrix.target }}
	if: matrix.target != 'wasm32-unknown-unknown'
	# WASM support
	- name: cargo build --target ${{ matrix.target }}
	run: |
	rustup target add ${{ matrix.target }}
	cargo build --target ${{ matrix.target }}
	if: matrix.target == 'wasm32-unknown-unknown'

And AArch64 Linux which is tier1 in rustc is not tested.

bytes/.github/workflows/ci.yml

Lines 106 to 113 in 3ab876f

	matrix:
	target:
	- i686-unknown-linux-gnu
	- armv7-unknown-linux-gnueabihf
	- powerpc-unknown-linux-gnu
	- powerpc64-unknown-linux-gnu
	- wasm32-unknown-unknown
	runs-on: ubuntu-latest

Solution

This PR adds aarc64-unknown-linux-gnu (ubuntu-22.04-arm) to matrix of tests on stable ("stable" job), and update "cross" job to run tests by using setup-cross-toolchain-action which is used in tokio. (see also tokio-rs/tokio#7123 for AArch64/Armv7hf)

As for WASM testing, use wasm32-wasip1 instead of wasm32-unknown-unknown because wasm32-wasip1 can test with cargo test command. (Testing wasm32-unknown-unknown usually needs wasm-pack or other commands.)