There is an `exec()` helper provided by `utils/shelljs.ts`, which is a
wrapper around ShellJS' `exec()` with some default options (currently
`silent: true`). The intention is to avoid having to pass these options
to every invocation of the `exec()` function.
This commit updates all code inside `dev-infra/` to use this helper
whenever possible).
NOTE: For simplicity, the `utils/shelljs` helper does not support some
of the less common call signatures of the original `exec()`
helper, so in some cases we still need to use the original.
PR Close#37444
d4c0962c7b