sim: Get rid of the Arguments class.

sim: Get rid of the Arguments class.

This class read arguments using the arch specific getArgument function
and then presented the arguments as an array. The problem with that
approach is that it's not possible to tell where different arguments
are without knowing the types of previous arguments, and not all
arguments can be simply represented as a native sized integer.

This class has been phased out and is no longer needed.

Change-Id: Ibb4c529fe8c51fd0ae15ed3b6ea30543ad9c23e0
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/24115
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>