Switch GetterOfProducts to use Event::getByToken

Performance measurements by Vincenzo Innocente showed that the HLT was spending too much time in edm::GetterOfProducts. The time was caused by safety checks in Event::getByLabel. This code changes the class to use Event::getByToken which avoids those checks by design.

This also includes a fix for a typo in the name of EDGetToken*::isUninitialized as well as a bug fix which prevented getByToken to work for Runs and Lumis.