fix: generator tolayout in cling (#1613)

* bugfix for record tolayout

* pylint suggestion fix

* update fieldindex

* use conenttypes attribute instead of contents to match Numba code

* add accessor to layout in a generated RecordView

* fix tolayout of the indexedoption and union array generators, add tests

* fix tolayout of the indexed array generator

* fix tolayout of bitmasked and bytemasked array generators

* fix tolayout of unmasked array generator

* parametrize tests

* fix tolayout of regular array generator

* add tolayout of list array generator test

* add test for record

* address Jim's comment

* address Jim's comment

Co-authored-by: Jim Pivarski <jpivarski@users.noreply.github.com>