twister: deal with status/reason setting in handler in one place

Multiple handlers were setting status/reason in slightly different ways,
but the code was mostly trying to do the same. Put this code in the
handler class and implement in one place.

This fixes an issue where in some cases qemu failures were not handled
correctly and status of cases was not updated, leading to multiple
failures.

Signed-off-by: Anas Nashif <[email protected]>

Author: nashif