Merge pull request #14509 from lukesteensen/pg-array-defaults

remove calls to sql_type on pg columns
Conflicts:
	activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
	activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
	activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
	activerecord/test/cases/adapters/postgresql/array_test.rb