[ELF] order rela.dyn/rela.plt properly

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@177969 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF][Hexagon] add GOTREL/GOT relocations

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@177970 91177308-0d34-0410-b5e6-96231b3b80d8