[llvm-objcopy] Fix the behavior of --strip-* and --keep-symbol

If one runs llvm-objcopy --strip-all --keep-symbol foo
and the symbol table indeed contains the symbol "foo"
then it should not be removed.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D47052


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333008 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed