Fix stream closing when sending file with `ActionController::Live` included.

Fixes #12381
`core_ext/string/access.rb` test what we are documenting.

I also extracted the tests from a single bulk method into a separate test-case.
The new tests cover the API described in the docs.

There are two skipped tests, which are broken as of 2ef1fb2c455ca53a0c1e1768f50824926ce28bd3
* #to with negative Fixnum, position is counted from the end
* #from and #to can be combined

This was brought to my attention by #13627.

Closes #13627.
typo fix in test name. [ci skip].
Revert "Speedup String#to"

This reverts commit 2ef1fb2c455ca53a0c1e1768f50824926ce28bd3.

As described in PR #13627 this commit broke functionality when passing
a negative Fixnum to the `String#to` method:

```ruby
assert_equal "hell", s.to(-2)
```

Before the revert, this failed with:

```
  1) Failure:
StringAccessTest#test_#to_with_negative_Fixnum,_position_is_counted_from_the_end [test/core_ext/string_ext_test.rb:275]:
Expected: "hell"
  Actual: nil
```

This revert is to keep the functionality on `master` working.
If there is another way to get the performance benefit and keep
the documented functionality we can add that.

/cc @amatsuda @carlosantoniodasilva
create/drop test and development databases only if RAILS_ENV is nil

Closes #13625
Merge pull request #13629 from dmathieu/drop_test

Be more explicit about the default of db:drop and db:create
make `change_column_null` reversible. Closes #13576.

Closes #13623.
Minor typos fix [ci skip]
Move finish_template as the last public method in the generator
Fix typo [ci skip]
Merge pull request #13634 from jwworth/master

Fix typo [ci skip]
refactor generator tests to use block form of Tempfile
Merge pull request #13637 from craftsmen/app-generator-minor-fix

Move finish_template as the last public method defined in the generator
add a more restricted codepath for templates fixes #13390
clear cache on body close so that cache remains during rendering

fixes #13547

The body may use the local cache during rendering.  `call`ing the app
doesn't mean that rendering is finished, so we need to wait until
`close` is called on the body.
MySQL version 4.1 was EOL on December 31, 2009
We should at least recommend modern versions of MySQL to users.
Merge pull request #13644 from zzak/doc_mysql_config_template

MySQL version 4.1 was EOL on December 31, 2009 [ci-skip]
Adding Hash#compact and Hash#compact! methods

  * Adding Hash#compact and Hash#compact! methods
  * Using Ruby 1.9 syntax on documentation
  * Updating guides for `Hash#compact` and `Hash#compact!` methods
  * Updating CHANGELOG for ActiveSupport
  * Removing unecessary protected method and lambda for `Hash#compact` implementations
  * Performing `Hash#compact` implementation - https://gist.github.com/tinogomes/8332883
  * fixing order position
  * Fixing typo
Merge pull request #13632 from tinogomes/master

Adding Hash#compact and Hash#compact! methods
Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314