mw.Debug.profile: Tweak support check to handle PhantomJS

mw.Debug.profile: Tweak support check to handle PhantomJS

* Latest PhantomJS (1.9.7) supports Array.prototype.map,
  Array.prototype.reduce, Array.prototype.filter, and
  document.createElementNS, but not Function.prototype.bind
* Check all of these in the init function, and if they're available
  continue (unless there's no profiling data) and initialize
  this.createSvgElement (previously done inline)
* Accordingly, rename buildRequiresES5 to buildRequiresBrowserFeatures
  and tweak message

Change-Id: If464b1093ec445afbb6c6b8c230e0e2669ad8c5c