Merge: cleanup --no-check-*

Some people like to live dangerously, they unplug their usb stick without unmounting, they write long comments in a textbox in a browser, they eat pasta with a white t-shirt.
Now, they can also `--no-check-all` to disable all runtime-tests and sweat pure adrenaline.

Some numbers, because people like numbers: `--no-check-all` gives a small 6% boost for compiling nitg.
(for reference, --semi-global is a 20% boost).

Pull-Request: #665
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>

diff --cc src/abstract_compiler.nit
Simple merge

diff --cc src/global_compiler.nit
Simple merge

diff --cc src/separate_compiler.nit
Simple merge

diff --cc src/separate_erasure_compiler.nit
Simple merge