drm/i915/guc: Add basic GuC multi-lrc selftest

Add very basic (single submission) multi-lrc selftest.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-19-matthew.brost@intel.com