Run `riscv-arch-test` in CI pipeline

[jserv]

The build system is capable of running the tests for specific extensions, such as I, M, C, Zifencei, privilege, and F. However, there is no regular validation for each pull request and/or git commit regarding ISA compliance. We shall integrate riscv-arch-test into CI pipeline.

Expected output:

1. Fetch (custom) GNU Toolchain for RISC-V: ensure all ELF executables were stripped in advance, so that we can run CI pipeline a bit faster.
2. Run riscv-arch-test for RV32I and RV32M. Other extensions can be validated upon requested.
3. Show brief report for riscv-arch-test.

[jserv]

The xPack GNU RISC-V Embedded GCC provides pre-built toolchains for GNU/Linux, Microsoft Windows, and macOS. However, the typical file size of a archive file is more than 460MB, which not might fit the expectation for faster CI pipeline execution.

[jserv]

Considered as complete.