Remove angle_unittests swarming exception.

The ASAN+LSAN config was using 10 shards, each of which was taking
about 15 seconds. This seems unnecessary.

Bug: angleproject:5124
Change-Id: I968c3b31cb0464096052fbd4614b2f7efde2c36a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2517043Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823629}

testing/buildbot/chromium.memory.json

@@ -3306,8 +3306,7 @@
               "os": "Ubuntu-16.04"
             }
           ],
-          "service_account": "chromium-tester@chops-service-accounts.iam.gserviceaccount.com",
-          "shards": 10
+          "service_account": "chromium-tester@chops-service-accounts.iam.gserviceaccount.com"
         },
         "test": "angle_unittests",
         "test_id_prefix": "ninja://third_party/angle/src/tests:angle_unittests/",

testing/buildbot/test_suite_exceptions.pyl

@@ -102,13 +102,6 @@
       'linux-lacros-tester-rel',
       'linux-lacros-tester-fyi-rel',
     ],
-    'modifications': {
-      'Linux ASan LSan Tests (1)': {
-        'swarming': {
-          'shards': 10,
-        },
-      },
-    },
   },
   'angle_white_box_tests': {
     'remove_from': [