[ci] scripts: rewrite unittest to use expect

[zhangxp1998]

Rewrite the python-based unittest script into two distinct expect scripts: one for testing UEFI integration and another for executing general unittests. This allows FAT tests to accurately evaluate hardware dependencies by keeping virtio block devices out of the general unittest environment. Updates GitHub CI configurations to depend on the 'expect' utility and invoke both shell scripts instead of python.

[Copilot]

Pull request overview

This PR replaces the prior Python-based QEMU test harness with two Expect-based scripts: one focused on UEFI “Hello World” integration (with virtio-blk attached) and one focused on running LK unit tests in a “clean” QEMU environment (no virtio-blk), and updates GitHub Actions to install expect and run both scripts.

Changes:

• Added an Expect-driven unit test runner (ut all) for qemu-virt-arm64-test without virtio devices.
• Added an Expect-driven UEFI integration test that attaches a virtio-blk device and runs uefi_load virtio0.
• Updated Rust/Clang CI workflows to install expect and invoke the two new scripts; removed the legacy scripts/unittest.py.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
scripts/unittest.sh	New Expect script that boots QEMU and runs ut all, asserting on the unittest success/failure banner.
scripts/unittest.py	Removed legacy Python harness that booted QEMU with virtio-blk and validated UEFI “Hello World”.
scripts/uefi_unittest.sh	New Expect script that boots QEMU with virtio-blk attached and validates UEFI “Hello World!” output.
.github/workflows/github-ci-rust.yml	Installs expect and runs both new test scripts for qemu-virt-arm64-test.
.github/workflows/github-ci-clang.yml	Installs expect and runs both new test scripts for qemu-virt-arm64-test.

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