Store whether a symbol is a comdat signature in MCSymbolELF.

With this getBinging can now return the correct answer for all cases not
involving a .symver and the elf writer doesn't need to patch it last minute.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238980 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed