MdeModulePkg and SecurityPkg Variable: Enhance code to use the new variable data instead of old variable data when variable reclaim.

It can fix the potential failure to return EFI_OUT_OF_RESOURCES of the second variable set of large variable.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14822 6f19259b-4bc3-4df7-8a09-765794883524