iostest.bash: remove
iostest.bash: remove

There are no tethered iOS builders left, and should they appear in
the future, they should use all.bash.

Change-Id: I3217789514ffa725e4d2584e4991d899c5fda995
Reviewed-on: https://go-review.googlesource.com/c/go/+/259278
Trust: Elias Naur <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@eliasnaur.com>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>

CAFxX/go,cloudflare/go,golang/go,golang/go,golang/go,golang/go,CAFxX/go,CAFxX/go,nawawi/go,nawawi/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go,cloudflare/go,CAFxX/go,nawawi/go,cloudflare/go,CAFxX/go,cloudflare/go,nawawi/go,golang/go,CAFxX/go,golang/go,cloudflare/go,nawawi/go,nawawi/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go,cloudflare/go