Remove the obsolete prebuilt infrastructure files and disable multiarch.

SConstruct

 # -*- python -*-
 # Copyright (c) 2011 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.
 
 import atexit
 import glob
 import os
 import platform
 import stat
@@ skipping 2268 matching lines @@
     'tests/imc_sockets/nacl.scons',
     'tests/inbrowser_test_runner/nacl.scons',
     'tests/irt_hw/nacl.scons',
     'tests/libc_free_hello_world/nacl.scons',
     'tests/longjmp/nacl.scons',
     'tests/loop/nacl.scons',
     'tests/mandel/nacl.scons',
     'tests/math/nacl.scons',
     'tests/memcheck_test/nacl.scons',
     'tests/mmap/nacl.scons',
-    'tests/multiarch/nacl.scons',
+    # multiarch is disabled for now, as it doesn't test what it purports to.
+    # It was already disabled on Windows, irt, and ARM, and referred to the
+    # now obsolete prebuilt infrastructure.
+    # TODO(sehr): reenable multiarch or move to something similar.
+    #'tests/multiarch/nacl.scons',
     'tests/multiple_sandboxes/nacl.scons',
     'tests/nacl.scons',
     'tests/nacl_log/nacl.scons',
     'tests/nameservice/nacl.scons',
     'tests/nanosleep/nacl.scons',
     'tests/native_worker/nacl.scons',
     'tests/noop/nacl.scons',
     'tests/nrd_xfer/nacl.scons',
     'tests/nthread_nice/nacl.scons',
     'tests/null/nacl.scons',
@@ skipping 527 matching lines @@
 Default(['all_programs', 'all_bundles', 'all_test_programs', 'all_libraries'])
 
 if BROKEN_TEST_COUNT > 0:
   msg = "There are %d broken tests." % BROKEN_TEST_COUNT
   if GetOption('brief_comstr'):
     msg += " Add --verbose to the command line for more information."
   print msg
 
 # separate warnings from actual build output
 Banner('B U I L D - O U T P U T:')