Added commandline option --x86-min-inst-per-ctx
X86Context inst_count now counts insts, not uinsts

Also added uinst_count, wich counts uinsts.
With this change --x86-min-inst-per-ctx uses now insts, not uinsts.
This is the expected behaviour, since --x86-max-inst uses insts.
Spaces
If --x86-report and --min-inst-per-ctx print report

Print a report of the x86 cpu every time a ctx reaches the minimum of
instructions. The report is stored next to the normal --x86-report
printed at the ent of the execution but its format is "<x86-report>.pid<number>".
Also, the first core and thread that appear in the report are the ones
this ctx was last mapped.