Revert "Rename to test_mysql_strict_mode_disabled_dont_override_global_sql_mode"

This reverts commit babc24c1b07c1fd58b9b3249b0256f9b0d45c0f0.

Conflicts:

	activerecord/test/cases/adapters/mysql/connection_test.rb
	activerecord/test/cases/adapters/mysql2/connection_test.rb
Preparing for 4.1.6.rc1 release
Merge pull request #16349 from jmcnevin/master

Correctly determine if migration is needed.
Fixes the digits counter of AS's NumberToRoundedConverter

Zero has one digit, but Math.log10(0) returns -Infinity. The method
needs to special-case zero.

The patch adds a regression test that is not clearly related to the
underlying issue because digit_count is private and has no coverage.
Gray area.

This bug was uncovered by 60062cf.
Use latest 2.1 version of sprockets-rails
Merge pull request #16649 from Agis-/pg-columns-for-distinct

Fix postgresql adapter #columns_for_distinct trimming whitespace it shouldn't
CHANGELOG & improvements to #16649

* Require either FIRST or LAST qualifier for "NULLS ..."
* Require whitespace before "NULLS ..."
Merge pull request #16649 from Agis-/pg-columns-for-distinct

Fix postgresql adapter #columns_for_distinct trimming whitespace it shouldn't
CHANGELOG & improvements to #16649

* Require either FIRST or LAST qualifier for "NULLS ..."
* Require whitespace before "NULLS ..."

Conflicts:
	activerecord/CHANGELOG.md
Merge pull request #16664 from rubys/4-1-stable

Use latest 2.1 version of sprockets-rails
Clarify that unknown keys will become HTML attrs

Docs for all the other form tag helpers in this
file already clarify this.

[ci skip]
Remove erroneous form_tag option docs

This is true of the first param (url_for_options),
not of the second options param which is being
documented here.

[ci skip]
Merge pull request #16693 from tjschuck/form_for_doc_options_4-1

Backport: documentation update for form_for options
Fixed automatic maintaining test schema to properly handle sql structure schema format.

Additionally:
* It changes `purge` task on `sqlite3` adapter to recreate database file, to
be consistent with other adapters.
* Adds `purge` step when loading from `schema.rb`

Conflicts:
	activerecord/CHANGELOG.md
	railties/test/application/test_test.rb
Merge pull request #16316 from rails/senny/purge_schema_maintenance

purge database before loading schema, take 2
Conflicts:
	activerecord/CHANGELOG.md
	activerecord/lib/active_record/tasks/database_tasks.rb
remove deprecation warning which is not yet issued.

This will be deprecated with `4.2`. [ci skip]
fix, mysql `db:purge` respects `Rails.env`.

Previously this method always established a connection to the test database.
This resulted in buggy behavior when combined with other tasks like
`bin/rake db:schema:load`.

This was one of the reasons why #15394 (22e9a91189af2c4e6217a888e77f22a23d3247d1)
was reverted:

> I’ve replicated it on a new app by the following commands: 1) rails
  generate model post:title, 2) rake db:migrate, 3) rake
  db:schema:load, 4) rails runner ‘puts Post.first’. The last command
  goes boom. Problem is that rake db:schema:load wipes the database,
  and then doesn’t actually restore it. This is all on MySQL. There’s
  no problem with SQLite.

  -- DHH

https://github.com/rails/rails/commit/22e9a91189af2c4e6217a888e77f22a23d3247d1#commitcomment-6834245

Conflicts:
	activerecord/CHANGELOG.md
Merge pull request #16739 from y-yagi/patch-6

[ci skip] Fix example code of ActiveRecord::FixtureSet.context_class
Merge pull request #16756 from huoxito/dont-mess-railties-default-order

Dont mess with default order engines load (4.1.6.rc1 regression)
Merge pull request #16756 from huoxito/dont-mess-railties-default-order

Dont mess with default order engines load (4.1.6.rc1 regression)