expect-post: Introduce post-expect scripts to match logs post-factum

Currently LAVA cannot peform test matching on any UARTs but the main
one (UART0). However, existing expect scripts for other UARTs are
simple and just passively parse the output. So, it's possible to
just capture the UART output to a log file (what LAVA already does)
and then parse and analyze this log file. This is exactly the idea
behind post-expect scripts: where e.g. expect/tsp.exp would be run
by ArmCI (in parallel with other expect scripts), OpenCI will run
expect-lava/tsp.exp - after LAVA tests finished and logs are captured.

Currently, post-expect scripts are intended to handle all UARTs but
UART0 (UART0 is handled by lava-expect/ instead).

The directory is named `expect-post` to sort together with `expect`
and so relationship between them is clearer.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I8659d2e4740dcd8050bf72c035bf31481bd69b16
4 files changed