d8d6bd5e makes fixture loading to bulk statements by using
`execute_batch` for sqlite3 adapter. But `execute_batch` is slower and
it caused the performance regression for fixture loading.

In sqlite3 1.4.0, it have new batch method `execute_batch2`. I've
confirmed `execute_batch2` is extremely faster than `execute_batch`.
So I think it is worth to upgrade sqlite3 to 1.4.0 to use that method.

Before:

```
% ARCONN=sqlite3 bundle exec ruby -w -Itest test/cases/associations/eager_test.rb -n test_eager_loading_too_may_ids
Using sqlite3
Run options: -n test_eager_loading_too_may_ids --seed 35790

# Running:

.

Finished in 202.437406s, 0.0049 runs/s, 0.0049 assertions/s.
1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
ARCONN=sqlite3 bundle exec ruby -w -Itest  -n test_eager_loading_too_may_ids  142.57s user 60.83s system 98% cpu 3:27.08 total
```

After:

```
% ARCONN=sqlite3 bundle exec ruby -w -Itest test/cases/associations/eager_test.rb -n test_eager_loading_too_may_ids
Using sqlite3
Run options: -n test_eager_loading_too_may_ids --seed 16649

# Running:

.

Finished in 8.471032s, 0.1180 runs/s, 0.1180 assertions/s.
1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
ARCONN=sqlite3 bundle exec ruby -w -Itest  -n test_eager_loading_too_may_ids  10.71s user 1.36s system 95% cpu 12.672 total
```

Make Resolver#find_all_anywhere equivalent to #find_all

Add test that the listen gem is included when RUBY_ENGINE is not 'ruby'

* Add example for has_many :through source/source_type

* Add example for has_one :through source/source_type

Previously, when using `render file:`, it was possible to render files
not only at an absolute path or relative to the current directory, but
relative to ANY view paths. This was probably done for absolutely
maximum compatibility when addressing CVE-2016-0752, but I think is
unlikely to be used in practice.

Tihs commit removes the ability to `render file:` with a path relative
to a non-fallback view path.

Make FallbackResolver.new private

To ensure nobody is making FallbackResolvers other than "/" and "".

Make reject_files_external_... no-op for fallbacks

Because there are only two values used for path: "" and "/", and
File.join("", "") == File.join("/", "") == "/", this method was only
testing that the absolute paths started at "/" (which of course all do).

This commit doesn't change any behaviour, but it makes it explicit that
the FallbackFileSystemResolver works this way.

Remove outside_app_allowed argument

Deprecate find_all_anywhere

This is now equivalent to find_all

Remove outside_app argument

Deprecate find_file for find

Both LookupContext#find_file and PathSet#find_file are now equivalent to
their respective #find methods.

Cache database version in schema cache

  * The database version will get cached in the schema cache file during the
    schema cache dump. When the database version check happens, the version will
    be pulled from the schema cache and thus avoid querying the database for
    the version.
  * If the schema cache file doesn't exist, we'll query the database for the
    version and cache it on the schema cache object.
  * To facilitate this change, all connection adapters now implement
    #get_database_version and #database_version. #database_version returns the
    value from the schema cache.
  * To take advantage of the cached database version, the database version check
    will now happen after the schema cache is set on the connection in the
    connection pool.

* The fix is already in master since https://github.com/rails/rails/pull/34243
* See https://github.com/rails/rails/pull/35482 for the fix in Rails 5.2

Add rake db:prepare entry to the CHANGELOG.md

[ci skip]

`original_app_name` is used to show error message if giving app name is
invalid, it should be shown raw app name.

[ci skip] Doc for shallow: false options should use <tt> for better readability. 

`@changed_attributes` is no longer used since #30985.

* s/Postgres/PostgreSQL/
* s/MYSQL/MySQL/, s/Mysql/MySQL/
* s/Sqlite/SQLite/

Replaced all newly added them after 6089b314.

Fixed description of the `cache_key_with_version` method [skip ci]

Add `after_save_commit` callback as shortcut for `after_commit :hook, on: [ :create, :update ]`. (#35804)

Honor shallow: false on nested resources

Add attachment and attachments field generators

Hash / HashWithIndifferentAccess speed improvements

* Remove unnecessary variable from ActionCable.createWebSocketURL

* Improve ActionCable test by creating the Consumer before reassigning URL

With this change, the test now actually verifies that the Consumer's url
property changes dynamically (from testURL to `${testURL}foo`).

* Fix alphabetization of ActionCable exports

Add db:prepare rake task.

[ci skip] Updated the doc after renaming Template::File -> Template::RawFile in #35826

Rename `Template::File` to `Template::RawFile`

Rename `connection` option to `database` in `dbconsole` command

[ci skip] Fix typo for recieve -> receive

We introduced `connection` option for specifying spec with 1acd9a64.
But now we are using the `database` to specify the same value in other commands.

* https://github.com/rails/rails/blob/0a0f115031b64b5335fa88543c40df4194dfb428/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb#L11
* https://github.com/rails/rails/blob/0a0f115031b64b5335fa88543c40df4194dfb428/activerecord/lib/rails/generators/active_record/model/model_generator.rb#L17

The options provided to the users should be uniform. Since the term
"database" is used in rake task etc, So I want to be able to use it in
`dbconsole` command.

Also I deprecated the `connection` option because I think that it
would be confusing if there are multiple options to specify a same value.