pg_upgrade:  use "" rather than '', for Windows
If we ever support unix sockets on Windows, we should use "" rather than
'' for zero-length strings on the command-line, so use that.
Add a convenience routine makeFuncCall to reduce duplication.

David Fetter and Andrew Gierth, reviewed by Jeevan Chalke
pg_dump docs:  use escaped double-quotes, for Windows
On Unix, you can embed double-quotes in single-quotes, and via versa.
However, on Windows, you can only escape double-quotes in double-quotes,
so use that in the pg_dump -t/table example.
Backpatch to 9.3.
Report from Mike Toews