Clean up 'post-thumbnail' theme support unit tests.

* Separate into smaller test methods.
* Remove incorrect tests. A number of assertions in the existing test have always incorrectly described the behavior of `current_theme_supports( 'post-thumbnails' )`, but no one ever noticed because the tests had been designed to bail when `_wp_render_title_tag()` did not exist. The failures finally became visible when that function was introduced in [30074].

See #18548.

git-svn-id: https://develop.svn.wordpress.org/trunk@30148 602fd350-edb4-49c9-b593-d223f7449a82
Relocate hook docs so they directly precede the hook lines moved into foreach statements in [30140].

It's necessary for hook docs to directly precede hook lines so the parser can correctly match them up. This change relocates hook docs for `update_{$meta_type}_meta`, `update_postmeta`, `updated_{$meta_type}_meta`, and `updated_postmeta`.

Fixes #11683.


git-svn-id: https://develop.svn.wordpress.org/trunk@30149 602fd350-edb4-49c9-b593-d223f7449a82
Fix a couple of spacing and wrapping indents in the `WP_Date_Query::__construct()` hash notation.

See [30142]. See #28063.


git-svn-id: https://develop.svn.wordpress.org/trunk@30150 602fd350-edb4-49c9-b593-d223f7449a82
Expand and clarify tests for get_blog_post()

Remove unnecessary user factory use. Be explicit about test scenarios.

See #30080


git-svn-id: https://develop.svn.wordpress.org/trunk@30151 602fd350-edb4-49c9-b593-d223f7449a82
Split tests for is_main_site()

Break multiple assertions from one method into multiple methods with one assertion each.

See #30080


git-svn-id: https://develop.svn.wordpress.org/trunk@30152 602fd350-edb4-49c9-b593-d223f7449a82