[llvm-objcopy] Switch over to using TableGen for parsing arguments

Swithces from using the command line library to using TableGen. This will allow
llvm-strip to exist and allow refinements of the command line syntax.

Differential Revision: https://reviews.llvm.org/D44236

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329863 91177308-0d34-0410-b5e6-96231b3b80d8
12 files changed