Remove --full-results-html from rwt invocation for swarming

This flag shouldn't affect test runs here; see bug.

Bug: 748623
Change-Id: Ic4937b1ad174c60bc758e22851177d69105293a0
Reviewed-on: https://chromium-review.googlesource.com/585359Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Quinten Yearsley <qyearsley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491562}

testing/buildbot/gn_isolate_map.pyl

@@ -1112,7 +1112,6 @@
       "../../third_party/WebKit/Tools/Scripts/run-webkit-tests",
       "--seed", "4",
       "--no-show-results",
-      "--full-results-html",
       "--clobber-old-results",
       "--exit-after-n-failures", "5000",
       "--exit-after-n-crashes-or-timeouts", "100",