Bring back browser_tests on Mac10.13 as non-experimental.

The bots appear to be stable with the test filter in place.

Bug: 828031
Change-Id: I50f12e581dbc1e3832687326f71505b92ee5d73d
Reviewed-on: https://chromium-review.googlesource.com/c/1299655
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602841}
diff --git a/testing/buildbot/chromium.mac.json b/testing/buildbot/chromium.mac.json
index 693ecbb..7303394 100644
--- a/testing/buildbot/chromium.mac.json
+++ b/testing/buildbot/chromium.mac.json
@@ -3614,7 +3614,6 @@
           "--test-launcher-filter-file=../../testing/buildbot/filters/mac_window_server_killers.browser_tests.filter",
           "--gtest_shuffle"
         ],
-        "experiment_percentage": 50,
         "swarming": {
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index 4ab2b24..57293ea 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -139,7 +139,6 @@
           '--test-launcher-filter-file=../../testing/buildbot/filters/mac_window_server_killers.browser_tests.filter',
           '--gtest_shuffle',
         ],
-        'experiment_percentage': 50,
         'swarming': {
           'dimension_sets': [
             {