[test][prefix][two_loops] Use integer_offsetter algorithm

This patch updates the naming of the blocks as well as
change the algorithm used in the blocks part.

This allows to improve testing for the beat/beat.editor> v2
version.
2 jobs for <span class="ref-name">improve_two_loops_testing</span> in 22 minutes and 16 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #171186
docker-build
build_linux_36

00:21:26

64.0%
passed #171187
macosx
build_macosx_36

00:22:16

64.0%