BaseTools: process the files by the priority in BUILDRULEORDER

BaseTools: process the files by the priority in BUILDRULEORDER

By the BUILDRULEORDER feature to process files listed in INF [Sources]
sections in priority order, if a filename is listed with multiple
extensions, the tools will use only the file that matches the first
extension in the space separated list.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19686 6f19259b-4bc3-4df7-8a09-765794883524