Fix WebKit Win10 14393 tag to match updated Windows version.

BUG=828051

Change-Id: I68e2285c72c7722c8380d143d10a0c42e0c43877
Reviewed-on: https://chromium-review.googlesource.com/989669
Reviewed-by: John Budorick <[email protected]>
Commit-Queue: Jao-ke Chin-Lee <[email protected]>
Cr-Commit-Position: refs/heads/master@{#547461}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index d160e9b2..eedee3d3 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -3694,7 +3694,7 @@
         'swarming': {
           'dimension_sets': [
             {
-              'os': 'Windows-10-14393',
+              'os': 'Windows-10-15063',
             },
           ],
         },