Uploader: update to 1.5.1.1, remove plupload.full.js (we cannot use it),...

Uploader: update to 1.5.1.1, remove plupload.full.js (we cannot use it), rename the script handle in script-loader to avoid any confusion, fixes #19187

git-svn-id: https://core.svn.wordpress.org/trunk@19194 1a063a9b-81f0-0310-95a4-ce76da25c4cd