New files required by DumpRenderTree and testsuite.
Graphics context: support CompositeDestinationOut

We happen to have a matching drawing mode.

Explicitly add the other missing ones, and send debug messages to stderr
to avoid cluttering the tests.
Send JS console messages to WebWindow

This allows redirecting the messages to a graphical JS console instead
of the terminal. DRT also needs this, as it sends them to standard
output and needs a common format with other ports.