Remove failing uploadfile test in trunk

The test has been added to #11946 and can be readded when that ticket is fixed.

Props MikeHansenMe for creating patch of current unit test

See #30284


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git-svn-id: http://core.svn.wordpress.org/trunk@30288 1a063a9b-81f0-0310-95a4-ce76da25c4cd