[test] Let full-debug builder run with normal priority

When the builder was moved to the main console it should have gotten
a higher priority for tests as otherwise it's affected of bot
shortage as in the bug below.

No-Try: true
Bug: v8:11566
Change-Id: Ide63f3659a8791e5ef4b48fc62504bc06bd09453
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2762149
Auto-Submit: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73421}

infra/testing/builders.pyl

@@ -962,11 +962,6 @@
     'swarming_dimensions': {
       'os': 'Ubuntu-16.04',
     },
-    'swarming_task_attrs': {
-      'expiration': 14400,
-      'hard_timeout': 3600,
-      'priority': 35,
-    },
     'tests': [
       {'name': 'v8testing', 'variant': 'default', 'shards': 4},
     ],