[pdb] Write the IPI stream.

The IPI stream is structurally identical to the TPI stream, but it
contains different record types.  So we just re-use the TPI writing
code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281638 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed