oeqa/runtime/parselogs: parse the logs with Python, not grep

oeqa/runtime/parselogs: parse the logs with Python, not grep

Instead of constructing huge grep statements, we can simply open the logs
in Python and do the relevant string operations directly.

The trick is to remember to casefold() all of the strings, so that the
"in" operator can be used.

Just one of the ignores needs to be adjusted because it uses a regular
expression and the new logic doesn't support that.  This is handled
by simply reducing the size of the ignore match.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>