Remove --vex-iropt-precise-memory-exns, implement --vex-iropt-register-updates

* Option --vex-iropt-precise-memory-exns has been removed.
  It is replaced by --vex-iropt-register-updates which accepts
  3 values : 'unwindregs-at-mem-access' (replacing
  --vex-iropt-precise-memory-exns=no), 'allregs-at-mem-access'
  (replacing --vex-iropt-precise-memory-exns=yes)
  and a new value 'allregs-at-each-insn'.
  'allregs-at-each-insn' allows the Valgrind gdbserver to always
  show up to date values to GDB.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12809 a5019735-40e9-0310-863c-91ae7b9d1cf9
8 files changed