Fix ActiveSupport::Testing::Isolation on jruby

Hopefully the first of many related to #11700.

With these changes the railties tests wont 100% pass but at least they
will run and show the errors.

The first problem was the @method_name variable was never set.
This was causing ENV["ISOLATION_TEST"] to always be nil which
would cause the test output to never be written to the tempfile.

The second problem was that an invalid -t option was being passed
to minitest and minitest was erroring out.

The third problem was the run method needs to always return an
instance of the test class it is trying to isolate. We were returning
a ProxyTestResult instead.
fix the changelog typo[ci skip]
Removed redundant xml override from pg adapter

Closes: #11706
Merge pull request #11713 from rajcybage/fix_changelog

Fix changelog typos [ci skip]
Remove useless begin..end
Use map! to avoid an extra object creation
Replaced quotation marks for term by apostrophe

in getting started guide for section 5.6

[ci skip]
map => map! for stopping extra array creation
Merge pull request #11717 from rajcybage/fix_map

map => map! for stopping extra array creation
Merge pull request #11714 from jetthoughts/11706_remove_bad_override_of_xml

Removed redundant xml override from pg adapter
Use assert_nil instead of testing for equality
fix a gramatical mistake
Merge pull request #11718 from rShetty/patch-4

fix a gramatical mistake
Define enable_extension method to prevent undefined method error

When mixing postgresql and another adapter like sqlite3 (for dev and test
respectively), the task `db:test:prepare` will fail due to the `enable_extension`
method not being defined in the abstract adapter. This patch simply adds an
empty definition to prevent it.
Merge pull request #11455 from antonio/fix_enable_extension_not_being_defined

Define enable_extension method to prevent undefined method error
Added action_view in Rails::Info
Merge pull request #11720 from arunagw/added-av-in-rails-info

Added action_view in Rails::Info
Merge pull request #11716 from jetthoughts/use_backquote_for_terms_in_getting_strated

Replaced quotation marks for term by apostrophes in getting started guide [ci skip]
As we are doing debug mode on

we don't need to silenced it
Merge pull request #11722 from arunagw/removed-deprecation-silenced-from-test

As we are doing debug mode on