Remove explicit win10 version for sync tests.

Fleet has been upgraded to Win10 1909, so this is a no-op that removes
no-longer-needed exception.

Bug: 1124829
Change-Id: I86aa7c4d85aa9bd57238f891a82dfc14ee43be4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2493099Reviewed-by: Erik Staab <estaab@chromium.org>
Commit-Queue: Ian Struiksma <ianstruiksma@google.com>
Cr-Commit-Position: refs/heads/master@{#820280}

testing/buildbot/test_suite_exceptions.pyl

@@ -2598,18 +2598,6 @@
           'shards': 6,
         },
       },
-      # TODO(crbug.com/1124829) Remove swarming config after
-      # version is moved to 1909.
-      'Win10 Tests x64': {
-        'swarming': {
-          'dimension_sets': [
-            {
-              'cpu': 'x86-64',
-              'os': 'Windows-10-18363',
-            },
-          ],
-        },
-      },
       'Win10 Tests x64 (dbg)': {
         'experiment_percentage': 100, # https://crbug.com/840369
       },