VG_(synth_fault_*), which synthesize faults as if an instruction had
caused a CPU fault. This is used in two places: one in vg_translate.c,
when trying to fetch instructions from bad memory, and the other in
vg_ldt.c, when using a bad segment register. This fixes a bug where an
assertion would fail rather than getting a useful message.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@2324
