Merge branch 'bugfix/avoid-get-option-in-innermost-loops' into 'master'

ref:extensions/dune-codegen This fixes a code generation performance bug in
sum factorized code. It also reveals that statistic profiling could be
superhelpful to us.

See merge request [extensions/dune-codegen!301]

  [extensions/dune-codegen!301]: gitlab.dune-project.org/extensions/dune-codegen/merge_requests/301