Make the "python" command resemble the standard Python interpreter

[Tom Tromey]

>>>>> "Doug" == Doug Evans <dje@google.com> writes:

Paul> Yes, but I think the benefits outweigh the small imcompatibility.

Doug> Yes and no.
Doug> - I may want a script that invokes python interactively.
Doug> - How do I write a gdb macro that invokes the python repl?

I think:

(gdb) python gdb.execute('python', from_tty = True)

This is sort of weird, but I think it is ok to require a weird command
to fill an unusual need.

Tom