Query logger shouldn't deal with time formatting

The query time in logger should not use number_format. With times >1000ms a comma is added to the number, e.g. 1,203.34. IMO the logger shouldn't care about the format, it should store the value in a workable way. Otherwise packages that use the information have a hard time to e.g. calculate the sum of times.

Example: https://github.com/loic-sharma/profiler/issues/30

I propose to either ditch the number_format, or, as shown, to round with 2 decimals, which is probably the perfect compromise.