iotests: rebase qemu_io() on top of qemu_tool()

iotests: rebase qemu_io() on top of qemu_tool()

Rework qemu_io() to be analogous to qemu_img(); a function that requires
a return code of zero by default unless disabled explicitly.

Tests that use qemu_io():
030 040 041 044 055 056 093 124 129 132 136 148 149 151 152 163 165 205
209 219 236 245 248 254 255 257 260 264 280 298 300 302 304
image-fleecing migrate-bitmaps-postcopy-test migrate-bitmaps-test
migrate-during-backup migration-permissions

Test that use qemu_io_log():
242 245 255 274 303 307 nbd-reconnect-on-open

Copy-pastables for testing/verification:

./check -qcow2 030 040 041 044 055 056 124 129 132 151 152 163 165 209 \
               219 236 242 245 248 254 255 257 260 264 274 \
               280 298 300 302 303 304 307 image-fleecing \
               migrate-bitmaps-postcopy-test migrate-bitmaps-test \
               migrate-during-backup nbd-reconnect-on-open
./check -raw 093 136 148 migration-permissions
./check -nbd 205

# ./configure configure --disable-gnutls --enable-gcrypt
# this ALSO requires passwordless sudo.
./check -luks 149

# Just the tests that were edited in this commit:
./check -qcow2 030 040 242 245
./check -raw migration-permissions
./check -nbd 205
./check -luks 149

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20220418211504.943969-8-jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>