Add guards around loggers that may be called a lot

Some code called a huge number of times is using slf4j's logger with
3 or more args, which is the vararg version.
To get an idea of the impact of the implicit array allocation, I also added a bench.

- the impact of the array allocation is huge.
- the impact of the method calls is negligible (or may even be optimized away).
- for method called a lot, guarding the logger call with an if is an easy performance win by reducing generated garbage.