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/Shell.c

@@ -509,6 +509,7 @@ UefiMain (
           // Reset page break back to default.
           //
           ShellInfoObject.PageBreakEnabled        = PcdGetBool(PcdShellPageBreakDefault);
+          ASSERT (ShellInfoObject.ConsoleInfo != NULL);
           ShellInfoObject.ConsoleInfo->Enabled    = TRUE;
           ShellInfoObject.ConsoleInfo->RowCounter = 0;
 
@@ -2091,6 +2092,7 @@ ProcessCommandLineToFinal(
   if (EFI_ERROR(Status)) {
     return (Status);
   }
+  ASSERT (*CmdLine != NULL);
 
   TrimSpaces(CmdLine);