[patch/rfc] Use frame_type for sigtramp test in infrun.c

[Andrew Cagney]

> Why is this if needed in the first place?  Isn't this just to work around
> frame problems that caused step_over_function to not handle signal handlers
> correctly?  I.e. if we have new-style frames that work properly, can't we
> just skip that whole if?

Literally, who knows!  Do quote daniel, it's before my time :-)  Removal 
sounds tempting, but first I think I'll yank all the legacy paths.

Andrew