More Profiler class refactoring

More Profiler class refactoring

* Factored a ProfilerStandard class out of Profiler
* Profiler is now an abstract base class
* For b/c, using Profiler as the profiler switches to ProfilerStub
  to avoid trying to instantiate an abstract class
* Also factored out a small TransactionProfiler class
* Fixed fatal in "new ProfilerStub()" line in getInstance();
  Profiler has long since type hinted $params as an array
* Removed bogus debug var usage left in ProfilerMwprof::getRawData()
* Removed useless mTimeMetric stuff

Change-Id: I854dabba6c8b1fb7d92baca59ebd4af25878d11d