This adds method and tests for writing to a PDB stream. With
this, even a PDB stream which is discontiguous can be treated
as a sequential stream of bytes for the purposes of writing.
Reviewed By: ruiu
Differential Revision: http://reviews.llvm.org/D21157
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272369 91177308-0d34-0410-b5e6-96231b3b80d8
