check presence of CWD at the end of `run_shell_cmd` and try to return to original working directory if non-existent #776

	name: End-to-end test of EasyBuild in different distros
	on: [push, pull_request]
	jobs:
	build_publish:
	name: End-to-end test
	runs-on: ubuntu-latest
	strategy:
	matrix:
	container:
	- centos-8.5
	- fedora-36
	- opensuse-15.4
	- rockylinux-8.8
	- rockylinux-9.2
	- ubuntu-20.04
	- ubuntu-22.04
	fail-fast: false
	container:
	image: ghcr.io/easybuilders/${{ matrix.container }}-amd64
	steps:
	- name: Check out the repo
	uses: actions/checkout@v3

	- name: download and unpack easyblocks and easyconfigs repositories
	run: \|
	cd $HOME
	for pkg in easyblocks easyconfigs; do
	curl -OL https://github.com/easybuilders/easybuild-${pkg}/archive/5.0.x.tar.gz
	tar xfz 5.0.x.tar.gz
	rm -f 5.0.x.tar.gz
	done

	- name: Set up environment
	shell: bash
	run: \|
	# collect environment variables to be set in subsequent steps in script that can be sourced
	echo "export PATH=$PWD:$PATH" > /tmp/eb_env
	echo "export PYTHONPATH=$PWD:$HOME/easybuild-easyblocks-5.0.x:$HOME/easybuild-easyconfigs-5.0.x" >> /tmp/eb_env

	- name: Run commands to check test environment
	shell: bash
	run: \|
	cmds=(
	"whoami"
	"pwd"
	"env \| sort"
	"eb --version"
	"eb --show-system-info"
	"eb --check-eb-deps"
	"eb --show-config"
	)
	for cmd in "${cmds[@]}"; do
	echo ">>> $cmd"
	sudo -u easybuild bash -l -c "source /tmp/eb_env; $cmd"
	done

	- name: End-to-end test of installing bzip2 with EasyBuild
	shell: bash
	run: \|
	sudo -u easybuild bash -l -c "source /tmp/eb_env; eb bzip2-1.0.8.eb --trace --robot"

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