plugin: add qemu_plugin_outs helper

Having the plugins grab stdout and spew stuff there is a bit ugly and
certainly makes the tests look ugly. Provide a hook back into QEMU
which can be redirected as needed.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Aaron Lindsay <aaron@os.amperecomputing.com>
5 files changed