twister: tests: set ZEPHYR_BASE using export

    - name: Run pytest for twisterlib

      env:

        ZEPHYR_BASE: ./

        ZEPHYR_TOOLCHAIN_VARIANT: zephyr

      run: |

        export ZEPHYR_BASE=${PWD}

        echo "Run twister tests"

        PYTHONPATH=./scripts/tests pytest ./scripts/tests/twister

    - name: Run pytest for pytest-twister-harness

      env:

        ZEPHYR_BASE: ./

        ZEPHYR_TOOLCHAIN_VARIANT: zephyr

        PYTHONPATH: ./scripts/pylib/pytest-twister-harness/src:${PYTHONPATH}

      run: |

        export ZEPHYR_BASE=${PWD}

        echo "Run twister tests"

        pytest ./scripts/pylib/pytest-twister-harness/tests