Optimize the log entry search algorithm to save boot performance.

Optimize the log entry search algorithm to save boot performance.
1. Search from the first entry can be changed to Search from the end entry, because most End just follows its Start.
2. Match Start and End entry, the first comparison can be changed from Handle to EndTimeStamp, because only zero EndTimeStamp is required to be matched.

Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13367 6f19259b-4bc3-4df7-8a09-765794883524