Refine code to make it more safely.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Jaben Carsey <Jaben.carsey@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15593 6f19259b-4bc3-4df7-8a09-765794883524

ShellPkg/Application/Shell/ShellProtocol.c

@@ -460,6 +460,7 @@ EfiShellGetFilePathFromDevicePath(
           ASSERT((PathForReturn == NULL && PathSize == 0) || (PathForReturn != NULL));
 
           AlignedNode = AllocateCopyPool (DevicePathNodeLength(FilePath), FilePath);
+          ASSERT (AlignedNode != NULL);
 
           // File Path Device Path Nodes 'can optionally add a "\" separator to
           //  the beginning and/or the end of the Path Name string.'