ShellPkg/[hex]edit: use SimpleTextInEx to read console

ShellPkg/[hex]edit: use SimpleTextInEx to read console

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=682

Edit and HexEdit commands assume that SimpleTxtIn translates
Ctrl+<Alpha-Key> key combinations into Unicode control characters
(0x1-0x1A).

Such translation does not seem to be required by the UEFI spec.
Shell should not rely on implementation specific behavior.
It should instead use SimpleTextInEx to read Ctrl+<Alpha-Key> key
combinations.

The patch changes edit and hexedit to only consumes SimpleTextInEx
so that the implementation specific behavior dependency is removed.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reported-by: Felix <felixp@mail.ru>
Cc: Felix <felixp@mail.ru>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>