llvm-readobj: fix off-by-one error in COFFDumper

It printed out base relocation table header as table entry.
This patch also makes llvm-readobj to not skip ABSOLUTE entries
becuase it was confusing.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222299 91177308-0d34-0410-b5e6-96231b3b80d8