[MIPS] Adding validator for MIPS architecture.

src/trusted/validator_mips/testdata/test_forbidden_instructions.S

+# Copyright 2012 The Native Client Authors.  All rights reserved.
+# Use of this source code is governed by a BSD-style license that can
+# be found in the LICENSE file.
+# Copyright 2012 MIPS Technologies / RT-RK.
+
+#
+# Tests a few instructions that are always illegal in NaCl.
+#
+
+.globl _start
+_start:
+
+  eret               #ERROR, unsafe
+
+  li        $v0, 1   #system call code for print_int
+  la        $a0, 20  #integer for printing
+  syscall            #ERROR, this is forbidden in untrusted code,
+
+  break              #ERROR, unsafe
+
+  di                 #ERROR, unsafe
+  ei                 #ERROR, unsafe
+  wait               #ERROR, unsafe
+  teq $t1, $t2       #ERROR, unsafe
+  nop
+  deret              #ERROR, unsafe
+
+end_of_code: