* `wp_version_check()`, `wp_update_plugins()`, and `wp_update_themes()` do not return meaningful responses, and their responses are never handled by core. As such, they shouldn't alternately return `void` or `false`. "Returning" in those functions is just "bailing"
* In the same functions, `version.php` doesn't need to load if `WP_INSTALLING` is defined - the function will immediately bail, the values will never be read, and the globals won't be reset. I have unified the approach in all 3 functions.
* When returning filtered `$locale`, there is no need to set the variable twice.
* In `_maybe_update_core()`, `isset()` can take multiple values to bail before the call to `time()`, if necessary. This is a micro-optimization to prevent PHP from hitting the OS unnecessarily.
See #32444.
git-svn-id: https://develop.svn.wordpress.org/trunk@32635 602fd350-edb4-49c9-b593-d223f7449a82
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