Parser.py: auto-detect result values and summary

In the future, we will be able to override tests result values with a
config file and it will become more convenient to auto-detect the test
result values rather than hardcoding.

This changes a bit the summary table and group sections order and fields,
but is still arguably acceptable.

While at it, print a one line summary during execution.

Signed-off-by: Vincent Stehlé <vincent.stehle@arm.com>