Fix printenv non-UTF8

[RenjiSann]

Fixes #9701

[sylvestre]

this is the third pr for the same issue now :)
#9726
#9702

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/overlay-headers (passes in this run but fails in the 'main' branch)

[ChrisDryden]

#9726 is env and #9702 is printenv

[ChrisDryden]

Ideally you can take @RenjiSann 's implementation and @sylvestre 's tests, get the best of both PR's

[RenjiSann]

Replaced my test with @sylvestre's

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/basenc/bounded-memory is now passing!

[sylvestre]

many jobs are failing :)

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/basenc/bounded-memory is now passing!

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)
Note: The gnu test tests/dd/no-allocate was skipped on 'main' but is now failing.
Note: The gnu test tests/misc/write-errors was skipped on 'main' but is now failing.