ShellPkg: stop using EFI_HANDLE in place of EFI_HII_HANDLE

The UefiShell*CommandsLib instances have constructor functions that do
something like:

  gHiiHandle = HiiAddPackages (...);
  ...
  ShellCommandRegisterCommandName (..., gHiiHandle, ...);

and destructor functions that implement the following pattern:

  HiiRemovePackages (gHiiHandle);

The -- semantic, not functional -- problem is that "gHiiHandle" is
declared with type EFI_HANDLE, and not EFI_HII_HANDLE, in all of these
library instances, even though HiiAddPackages() correctly returns
EFI_HII_HANDLE, and HiiRemovePackages() takes EFI_HII_HANDLE.

Once we fix the type of "gHiiHandle", it causes sort of a butterfly
effect, because it is passed around widely. Track down and update all of
those locations.

The DynamicCommand lib instances use a similar pattern, so they are
affected too.

NOTE: in practice, this patch is a no-op, as both EFI_HII_HANDLE and
EFI_HANDLE are typedefs to (VOID*). However, we shouldn't use EFI_HANDLE
where semantically EFI_HII_HANDLE is passed around.

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>

ShellPkg/DynamicCommand/TftpDynamicCommand/Tftp.c

@@ -11,7 +11,7 @@
 #include "Tftp.h"
 
 #define IP4_CONFIG2_INTERFACE_INFO_NAME_LENGTH 32
-EFI_HANDLE   mTftpHiiHandle;
+EFI_HII_HANDLE   mTftpHiiHandle;
 
 /*
    Constant strings and definitions related to the message indicating the amount of
@@ -1087,14 +1087,14 @@ CheckPacket (
 
   @return HII handle.
 **/
-EFI_HANDLE
+EFI_HII_HANDLE
 InitializeHiiPackage (
   EFI_HANDLE                  ImageHandle
   )
 {
   EFI_STATUS                  Status;
   EFI_HII_PACKAGE_LIST_HEADER *PackageList;
-  EFI_HANDLE                  HiiHandle;
+  EFI_HII_HANDLE              HiiHandle;
 
   //
   // Retrieve HII package list from ImageHandle