Synthetic targets are special in that the built tests and
applications actually run as native applications on the host. This
means that there is no target to connect to. The test or application
can be run directly from the GDB console using:
(gdb) run
or from Insight by pressing the Run icon.
There is therefore no need to connect to the target or download the
application, so you should ignore GDB “target” and
“load” commands in any instructions found in other places
in the documentation.