Clean up ReportingObserver Intervention test.

This patch removes a few debugging artifacts that were left in the
reporting-observer/intervention.html layout test.

Change-Id: I132a73b87c32d9a2fdb83a241ef733cb61f727e9
Reviewed-on: https://chromium-review.googlesource.com/677976Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Paul Meyer <paulmeyer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504455}

third_party/WebKit/LayoutTests/reporting-observer/resources/intervention.js

 async_test(function(test) {
   var observer = new ReportingObserver(function(reports, observer) {
-    test.done();
-  window.console.log("************************************** IN OBSERVER");
     test.step(function() {
       assert_equals(reports.length, 1);
 
@@ -26,7 +24,6 @@ async_test(function(test) {
   var targetX = rect.left + rect.width / 2;
   var targetY = rect.top + rect.height / 2;
   document.body.addEventListener('touchstart', function(e) {
-    window.console.log("************************************** TOUCH " + e.type);
     e.preventDefault();
     test.done();
   });