[ELF] Add more absolute atoms. Simplify how they are resolved.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@174149 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF][x86-64] Add the _GLOBAL_OFFSET_TABLE_ Atom in the correct location.

Now we link against glibc without --noinhibit-exec.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@174150 91177308-0d34-0410-b5e6-96231b3b80d8