Fix some typo in method names, variables
compatability => compatibility
Merge pull request #10761 from vipulnsward/fix-typo-1

Fix some typo in method names, variables
Merge pull request #10762 from vipulnsward/change_compatibility

compatability => compatibility
replace class_eval by define_method in active_record/relation

The class_eval version is slower than the define_method version.

	modified:   activerecord/lib/active_record/relation/query_methods.rb