Rename enum value_name: to value_method:, fix some test warnings #2703

Job	Run time
mongodb_test (gemfiles/mongoid_6.gemfile)	3m 24s
postgres_test (gemfiles/rails_master.gemfile, 3.3, 1)	3m 19s
mongodb_test (gemfiles/mongoid_7.gemfile)	3m 9s
lint	1m 31s
postgres_test (gemfiles/rails_7.1_postgresql.gemfile, 3.3)	3m 11s
javascript_test	26s
system_tests	2m 23s
test (Gemfile, 3.4)	3m 14s
test (Gemfile, 2.7)	3m 6s
test (gemfiles/rails_7.0.gemfile, 3.1)	3m 45s
test (gemfiles/rails_master.gemfile, 3.2)	3m 50s
test (gemfiles/rails_7.0.gemfile, 3.2)	3m 23s
test (gemfiles/rails_7.1.gemfile, 3.3)	3m 41s
test (gemfiles/rails_master.gemfile, 3.3, 1, 1)	4m 12s
test (gemfiles/rails_master.gemfile, 3.4, 1, 1)	4m 5s
	46m 39s

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