With the previous change that enabled error propagation through
`inherit_errexit`, the script would fail if `errexit` was set, but
`inherit_errexit` was not. This is due to `shopt -p` exiting with an
error if the option is disabled. To work around this, use the exit
code instead of the text value returned by `shopt -p`.
Fixes#160869.
b549e7bbb5