target-i386: Re-introduce optimal breakpoint removal Before the last patch, we had an efficient loop that disabled local breakpoints on task switch. Re-add that, but in a more general way that handles changes to the global enable bits too. Signed-off-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>