buildbot: Fixing the arguments for webkit_tests_exparchive

These should make the swarming arguments closer to when run on the bots
locally.

BUG=524758

Review-Url: https://codereview.chromium.org/2700693003
Cr-Commit-Position: refs/heads/master@{#450950}
diff --git a/testing/buildbot/gn_isolate_map.pyl b/testing/buildbot/gn_isolate_map.pyl
index 67b5b43..608f565 100644
--- a/testing/buildbot/gn_isolate_map.pyl
+++ b/testing/buildbot/gn_isolate_map.pyl
@@ -1024,8 +1024,13 @@
     "args": [
       "--xvfb",
       "../../third_party/WebKit/Tools/Scripts/run-webkit-tests",
-      "--clobber-old-results",
+      "--seed", "4",
       "--no-show-results",
+      "--full-results-html",
+      "--clobber-old-results",
+      "--exit-after-n-failures", "5000",
+      "--exit-after-n-crashes-or-timeouts", "100",
+      "--debug-rwt-logging",
       "--results-directory", "${ISOLATED_OUTDIR}/layout-test-results",
     ],
   },