Support indexing vector of fixed size data such as vector of UInt64
Support indexing vector of fixed size data such as vector of UInt64

[groonga-dev,03014]

Reported by funa 1g. Thanks!!!

hiroyuki-sato/groonga,komainu8/groonga,cosmo0920/groonga,redfigure/groonga,komainu8/groonga,groonga/groonga,hiroyuki-sato/groonga,redfigure/groonga,kenhys/groonga,kenhys/groonga,hiroyuki-sato/groonga,naoa/groonga,cosmo0920/groonga,redfigure/groonga,cosmo0920/groonga,cosmo0920/groonga,komainu8/groonga,redfigure/groonga,hiroyuki-sato/groonga,hiroyuki-sato/groonga,hiroyuki-sato/groonga,cosmo0920/groonga,redfigure/groonga,komainu8/groonga,naoa/groonga,groonga/groonga,groonga/groonga,kenhys/groonga,kenhys/groonga,hiroyuki-sato/groonga,naoa/groonga,komainu8/groonga,kenhys/groonga,redfigure/groonga,redfigure/groonga,komainu8/groonga,redfigure/groonga,cosmo0920/groonga,groonga/groonga,cosmo0920/groonga,naoa/groonga,naoa/groonga,naoa/groonga,komainu8/groonga,groonga/groonga,cosmo0920/groonga,komainu8/groonga,kenhys/groonga,hiroyuki-sato/groonga,kenhys/groonga,groonga/groonga,naoa/groonga,kenhys/groonga,naoa/groonga,groonga/groonga,groonga/groonga