tests: Run lint tests with detected bash

When we invoke a shell script directly, the system selects a bash binary that might be different from the one detected by find_program('bash'). Explicitly use the one detected by Meson, matching the behavior of our other test() invocations on shell scripts.

Fixes test failure on Windows in GitHub Actions CI:

stdout: 1: UNKNOWN: Windows Subsystem for Linux has no installed distributions.
stdout: 2: UNKNOWN: Distributions can be installed by visiting the Microsoft Store:
stdout: 3: UNKNOWN: https://aka.ms/wslstore

Found-by: Benoit Pierre <benoit.pierre@gmail.com>
Fixes: d7601f7e ("Incorporate some lint checks into meson test")