Fixed in issue with ObjectFileMachO where it would add empty sections to the...

Fixed in issue with ObjectFileMachO where it would add empty sections to the section list that was used to try and cap symbols to the max address of the section in which it is contained. The empty sections would make cap the symbols and make their sizes zero. Also fixed a few other things that could cause problems in the SymbolFileDWARFDebugMap when zero sized symbols were found and used to make OSO range map entries.

<rdar://problem/25886773>

llvm-svn: 267237