Calling `load_plugin_textdomain( 'textdomain' )` shouldn't cause an extra file stat call

[dd32]

Thanks to WordPress.org Language packs, plugins no longer need to ship with translations nor a languages directory.

However, if a plugin simply calls load_plugin_textdomain( 'textdomain' ); it causes WordPress to look for WP_PLUGINS_DIR/textdomain-locale.mo.

I think we should be able to avoid looking for a translation file in this case.

[swissspidy]

See also: #34213

[johnbillion]

See also: #34114

[ocean90]

Duplicate of #34213.