refactor(benchmarks): add cloud reporter, add params

- adds console and cloud reporter (via Google BigQuery).
- makes parameters of tests explicit and modifiable.
- removes `detect` and `ignoreGc` mode from benchpress
  as these can result in unstable numbers.

tools/build/snippets/url_params_to_form.js

@@ -0,0 +1,14 @@
+// helper script that will read out the url parameters
+// and store them in appropriate form fields on the page
+(function() {
+  var regex = /(\w+)=(\w+)/g;
+  var search = decodeURIComponent(location.search);
+  while (match = regex.exec(search)) {
+    var name = match[1];
+    var value = match[2];
+    var els = document.querySelectorAll('input[name="'+name+'"]');
+    for (var i=0; i<els.length; i++) {
+      els[i].value = value;
+    }
+  }
+})();