Revert "IR: Simplify DIBuilder's HeaderBuilder API, NFC"

This reverts commit r226540, since I hit an unexpected bot failure [1].
I'll investigate.

[1]: http://bb.pgr.jp/builders/cmake-llvm-x86_64-linux/builds/20244

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226542 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed