oeqa/utils/qemurunner: support ignoring vt100 escape sequences

oeqa/utils/qemurunner: support ignoring vt100 escape sequences

If we talk to terminals that like colors, we need to ignore the vt100
escape sequences when matching strings.

An unprocessed barebox console prompt would e.g. look like:

  ESC[1;32mbarebox@ESC[1;36mARM QEMU virt64:/ESC[0m

where we cannot match for something like "barebox@ARM QEMU virt64:/".
The same applies to colored Linux terminal output of course.

The "\x1b\[" from the regex catches the standard start of ANSI escape
sequence while the rest catches the actual command code executed.

Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>