hnbgw: call f_start_hnbs() by default

Most tests need to run f_start_hnbs() directly after f_init(), so make
that the default behavior.

The three tests that don't want f_start_hnbs() to run now pass a new
arg, f_init(start_hnb := false).

Change-Id: I2b29ce66aee0b2d57fa26e6110f06292c481ab6b
1 file changed