Adjust PEObjectWriter to not emit data into separate sections for separate image data directories

[jkoritzinsky]

Possible ways we could implement this:

1. Hardcode specific node kinds and propagate them down from ObjectWriter into PEObjectWriter.
2. Add a concept of "synthetic" sections (possibly like the grouped sections concept in COFF) to allow us to identify specific data directories without hard-coding specific node class types.

Context #121186 (comment)