stty: print non-default control characters

[yuankunzhang]

Closes #8228 .

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/stdbuf (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)

[sylvestre]

@willshuttleworth wdyt about that ? :)

[willshuttleworth]

the parts that close #8228 seem good. the issue is that the pr includes changes beyond the scope of #8228, namely implementing the sane combination. #8256 is waiting to be merged and also implements the sane combination, but also all other combination settings that exist. i think if this gets reworked after #8256 is merged, that would be best.

[willshuttleworth]

@yuankunzhang now that #8256 is merged, you are welcome to rework this and include the parts that handle printing sane values

[yuankunzhang]

@yuankunzhang now that #8256 is merged, you are welcome to rework this and include the parts that handle printing sane values

Thanks!

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/misc/stdbuf (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/tee (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/misc/stdbuf (passes in this run but fails in the 'main' branch)

[cakebaker]

Thanks!