[RFA] lib/gdb.exp: check skip_cplus_tests target info

[Michael Snyder]

Fernando Nasser wrote:
> 
> Nick Duffek wrote:
> >
> > The attached patch skips C++ tests if [target_info exists
> > gdb,skip_cplus_tests] is true, allowing C++ tests to be skipped by
> > changing the board description file instead of adding board-specific
> > checks to gdb.exp.
> >
> 
> I wonder if this is really board specific.  The capability of running
> C++ programs is related to the run time environment existent/loaded in the
> board. Sometimes a newlib that is linked to the program and loaded there,
> sometimes is part of an OS running there etc.
> 
> Would you mind elaborating a little bit more on this one?

Good thinking -- what is needed is a simple way to disable
the C++ tests, but maybe it should be an argument in the
RUNTESTFLAGS.

BTW, Nick, let me add my appreciation to Fernando's for all
the testsuite cleanups.