Teo Couprie Diaz authored Mar 30, 2023 and Beata Michalska committed Apr 04, 2023

Add a set of skip files for running the syscalls set of tests in compat
or purecap:
 - syscalls_morello_musl_skip skips all Musl related failures,
 - syscalls_morello_skip is for tests skipped and not built for Morello,
 - syscalls_morello_purecap_skip is for tests skipped in purecap.

Update the README to reflect those additions and explain how to use
the skip files.

This is preparation for CI testing in Morello release 1.6 and later.
Signed-off-by: Teo Couprie Diaz <teo.coupriediaz@arm.com>