When appending a Windows drive letter to a file URL, remove any path we may have copied from the base URL
Created attachment 410444 [details] Patch
This patch modifies the imported WPT tests. Please ensure that any changes on the tests (not coming from a WPT import) are exported to WPT. Please see https://trac.webkit.org/wiki/WPTExportProcess
http://trac.webkit.org/r267964
<rdar://problem/69954009>