[yaml2elf] - Simplify code, add a test. NFC.

This simplifies the code allowing to set the sh_info
for relocations sections. And adds a missing test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339870 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed