ShellPkg: Add checking for memory allocation and pointer returns from functions.

signed-off-by: jcarsey
reviewed-by: geekboy15a

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12540 6f19259b-4bc3-4df7-8a09-765794883524

ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.c

@@ -145,6 +145,10 @@ TestNodeForMove (
   //
   CommandName   = NULL;
   CommandName   = StrnCatGrow(&CommandName, NULL, CommandNode->Cl, 0);
+  if (CommandName == NULL) {
+    return (FALSE);
+  }
+
   CommandNameWalker = CommandName;
   while(CommandNameWalker[0] == L' ') {
     CommandNameWalker++;