[PATCH]: Remove "xbreak" and "txbreak" to hppa target code.

[Michael Snyder]

Michael Snyder wrote:
> 
> These two commands were implemented in a completely non-portable
> way, so that they might work on hppa architecture, but would not
> be likely to work in general.
> 
> Removing them from core gdb and putting them in the hppa module.
> Leaving the code in breakpoint.c (it certainly can't live
> anywhere else), but it will not be called except from hppa-tdep.

Sure.  I'll send that separately.