ci: Make a530's GLES3/31 fractional runs much more complete.

Now that we don't get scheduled to any 19mhz CPUs, the old GLES3 job went
from 12 minutes of deqp-runner runtime to 54s.  Increase how much of the
testsuite we cover in exchange, still keeping the runtime at 3-6 min
(compared to previous 10-17 min).  Since the tests we're running changed,
reset the xfails list.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5115>

.gitlab-ci.yml

@@ -890,13 +890,15 @@ arm64_a530_gles3:
     DEQP_VER: gles3
     DEQP_PARALLEL: 1
     CI_NODE_INDEX: 1
-    CI_NODE_TOTAL: 100
+    CI_NODE_TOTAL: 40
 
 arm64_a530_gles31:
   extends:
     - arm64_a530_gles3
   variables:
     DEQP_VER: gles31
+    CI_NODE_INDEX: 1
+    CI_NODE_TOTAL: 10
 
 # RADV CI
 .test-radv: