The user has the rights of a public user execpt it can never create a project,
 group, or team. Also it cant view internal projects.

The rationale for this can be found in
https://gitlab.com/gitlab-org/gitlab-ce/issues/13718 but in short the
benchmark suite no longer serves a good purpose now that we have proper
production monitoring in place.

Fixes gitlab-org/gitlab-ce#13718

This ensures that blocks defines using "benchmark_subject" have access
to methods defined using let/subject & friends.

This class method can be used in "describe" blocks to specify the
subject of a benchmark. This lets you write:

    benchmark_subject { Foo }

instead of:

    benchmark_subject { -> { Foo } }