ShellPkg: Fix the support for command line comments.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Chris Phillips <chrisp@hp.com>
Reviewed-by: Jaben Carsey <Jaben.carsey@intel.com>


git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/ShellPkg@16126 6f19259b-4bc3-4df7-8a09-765794883524
Roll back check in r15180 which caused the shell always returns EFI_ABORTED no matter what exit-code is specified for "exit" command.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Carsey Jaben <jaben.carsey@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/ShellPkg@16127 6f19259b-4bc3-4df7-8a09-765794883524