Remove multiple GC calls and replace GCController.collect calls with GCController.collectAll

LayoutTests/resources/magnitude-perf.js

 // Magnitude verifies time complexity of a function.
 // Magnitude.run can be called multiple times in a single script if desired,
 // optionally with different parameters each time.
 //
 // Usage:
 // <script src="../resources/magnitude-perf.js"></script>
 // <script>
 // function setup(magnitude)
 // {
 //     ...
@@ skipping 181 matching lines @@
 
 Magnitude._runTime = function(setup, test, magnitude)
 {
     setup(magnitude);
 
     var debugStr = 'run for magnitude ' + magnitude;
     if (window.GCController) {
         if (GCController.getJSObjectCount)
             debugStr += ' jsObjectCountBefore ' + GCController.getJSObjectCount();
 
-        // Do a gc to reduce likelihood of gc during the test run.
-        // Do multiple gc's for V8 to clear DOM wrappers.
-        GCController.collect();
-        GCController.collect();
-        GCController.collect();
+        GCController.collectAll();
 
         if (GCController.getJSObjectCount)
             debugStr += ' jsObjectCountAfter ' + GCController.getJSObjectCount();
     }
 
     Magnitude._debug(debugStr);
 
     var nowFunction = window.performance && window.performance.now ?
         window.performance.now.bind(window.performance) : Date.now;
 
@@ skipping 134 matching lines @@
 };
 
 // Register listener
 window.addEventListener('load', function() {
     // FIXME: Add Magnitude.waitUntilDone/notifyDone for tests that need to
     // operate after the load event has fired.
     if (window.testRunner)
         document.body.innerHTML = '';
     document.body.appendChild(Magnitude._container);
 }, false);