Default to sorting user's test cases for now

Goals:

1. Default to :random for newly generated applications
2. Default to :sorted for existing applications with a warning
3. Only show the warning once
4. Only show the warning if the app actually uses AS::TestCase

Fixes #16769
Merge pull request #16839 from chancancode/default_test_order

Default to sorting user's test cases for now
Fix typo
Set the test order to be random in the generated app

This will avoid the warning in our tests. We delete all the
config/environments/ files in the test app so our default code will not
work.
Set test order in ActiveSupport::TestCase of isolation/abstract_unit
Define the configuration at Active Support
Always define capture to remove the deprecation message
A `NullRelation` should represent nothing. Closes #15176.

[Matthew Draper & Yves Senn]

Closes #16860. (pull request to discuss the implementation)
switch `assert_operator` arguments as discussed in #16860.

Working with two different machines is hard :sweat:
Changes puts to logger.info
Merge pull request #16874 from Bartuz/patch-1

[docs] Changes puts to logger.info [ci skip]
reuse view test-cases for pg materialized view tests.
pg, add test cases for updateable views.