Katarzyna Piecielska authored May 23, 2024 and Kamil Konieczny committed May 23, 2024

All Display tests are using Category field to show that these are
display tests. For Core we were having various values: Software building
block, Desktop client, Infrastructure, Server, Selftest, Obsolete, etc.
With Mega feature/Sub-category/Functionality properly set and aligned,
there is no need to have so many values in 'Category' field.

Let's have 'Category=Core' for all Core tests.
Adding change to xe_test_config.json and i915_test_config.json files to
show correct Category value and remove mandatory field.

Cc: Aditya Chauhan <aditya.chauhan@intel.com>
Cc: Gandi Ramadevi <ramadevi.gandi@intel.com>
Cc: Girotra Himanshu <himanshu.girotra@intel.com>
Cc: Kamil Konieczny <kamil.konieczny@linux.intel.com>
Signed-off-by: Katarzyna Piecielska <katarzyna.piecielska@intel.com>
Reviewed-by: Mauro Carvalho Chehab <mauro.chehab@linux.intel.com>