gdb.execute(to_string=True) doesn't capture signal notice anymore

Hi,

We have some code which uses the fact of GDB 7.7 behaviour that if you
execute python code like

    s = gdb.execute("run", to_string=True)

and, say, debuggee generates SIGTRAP, then result `s` includes the
string "Program received signal SIGTRAP, Trace/breakpoint trap."

What we see is that since 7.12.1 or earlier, and until now, this is no
longer the case - this message is not captured but is only printed to
terminal.

Before I dig into "fixing it", I want to know maintainers opinion - is
the current behaviour exactly what you like, or it's an unintended
regression and you'd prefer to preserve the old way?