Rollup merge of #121685 - fortanix:raoul/shellcheck_on_lvi_test_scrip…

…t, r=Mark-Simulacrum

Fixing shellcheck comments on lvi test script

Running `shellcheck` on `tests/run-make/x86_64-fortanix-unknown-sgx-lvi/script.sh` gives plenty of warnings. This PR fixes those issues. For completeness: #121683 fixes another warning as well