In `WP_Image_Editor_GD::_save()`, pass `$compression_level` into the args array for `->make_image()`.

Props MuViMoTV, markoheijnen, SergeyBiryukov, mikemanger, ericlewis.
Fixes #24380.



git-svn-id: https://develop.svn.wordpress.org/trunk@28640 602fd350-edb4-49c9-b593-d223f7449a82