More iwyu suggested headers removal

Signed-off-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>
Signed-off-by: Stephan Bergmann <sbergman@redhat.com>, undid one remove that was
detrimental to loplugin:unreffun

Change-Id: I18d8252084d828f94ef7a954e1dbfb45743d7970