Track method call times/counts as a single metric

This changes method call tracking so only a single metric is emitted regardless of the number of calls. This allows us to more accurately measure the total execution time of a method as well as the number of times a method is called. See 851e3ff7578973c2206628424eac3b951a3c656d for more details.

Method call tracking tracked calls individually meaning the end statistics may not always be accurate enough to get a good understanding of where time is spent.

See merge request !4754