Bump all of chromeos-kevin-rel's tests out of experimental.

chromeos-kevin-rel is a simplechrome bot running tests on kevin DUTs:
https://ci.chromium.org/p/chromium/builders/ci/chromeos-kevin-rel

This will enable chromium sheriff alerts for its 3 suites: all_tast_tests, sanity_test,
and base_unittests. (That third might not be the most useful; could be removed.)

I'll send out a PSA prior to landing.

R=jbudorick, martiniss

Bug: 866062
Change-Id: I3d8f853aacc41d1f381d18939a1b26b3ed4adbbb
Reviewed-on: https://chromium-review.googlesource.com/c/1478117Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634332}

testing/buildbot/chromium.chromiumos.json

@@ -411,7 +411,6 @@
         "args": [
           "--test-launcher-filter-file=../../testing/buildbot/filters/chromeos.base_unittests.filter"
         ],
-        "experiment_percentage": 100,
         "swarming": {
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
@@ -428,7 +427,6 @@
         }
       },
       {
-        "experiment_percentage": 100,
         "swarming": {
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
@@ -445,7 +443,6 @@
         }
       },
       {
-        "experiment_percentage": 100,
         "swarming": {
           "can_use_on_swarming_builders": true,
           "dimension_sets": [

testing/buildbot/test_suites.pyl

@@ -462,20 +462,13 @@
     },
 
     'chromeos_device_kevin_tests': {
-      # TODO(crbug.com/866062): Bump these out of experimental once the bot's
-      # got a few green builds.
       'base_unittests': {
         'args': [
           '--test-launcher-filter-file=../../testing/buildbot/filters/chromeos.base_unittests.filter',
         ],
-        'experiment_percentage': 100,
-      },
-      'chrome_kevin_tast_tests': {
-        'experiment_percentage': 100,
-      },
-      'cros_vm_sanity_test': {
-        'experiment_percentage': 100,
       },
+      'chrome_kevin_tast_tests': {},
+      'cros_vm_sanity_test': {},
     },
 
     'chromeos_isolated_scripts': {