Merge pull request #12532 from vipulnsward/singleton_class

Fix `singleton_class?`
Merge pull request #10538 from neerajdotname/3882

scope_chain should not be mutated for other reflections
only calculate offset index once. #12537
the preloader for the RHS has all the preloaded records, so ask it
simplify populating the ordering hash
Merge pull request #12536 from sbagdat/patch-1

Remove size alias for length validation
Add 2 tests, 1 of which fails, to isolate the digest_caching behaviour causing #12521

If config.action_view.cache_template_loading = false, most likely in a development
configuration if config.cache_classes = false &
config.action_controller.perform_caching = true.

config.action_view.cache_template_loading defaults to the value of config.cache_classes
Ensure ActionView::Digest.cache is correctly cleaned up when
ActionView::Resolver.caching = false.
update changelog
we should have unique sponsorable ids in the fixtures at least
read the association instead of sending
rm JoinHelper from JoinAssociation
remove delegation to `chain`
store aliases in a better structure
let the Table class build the ARel alias nodes
move alias building to the table node
keep a cache on the alias object
this method does not exist anymore
move column_names_with_alias on to the alias cache object
Merge pull request #12534 from vipulnsward/minor_number_helper_perfs

Minor Refactoring to `NumberHelper#number_to_human`