Update autotest tests to use make -j where possible.

client/site_tests/hardware_MemoryThroughput/hardware_MemoryThroughput.py

 # Copyright (c) 2009 The Chromium OS 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 re
 import os
 import logging
 
 from autotest_lib.client.bin import test
 from autotest_lib.client.common_lib import error, utils
 
 class hardware_MemoryThroughput(test.test):
     version = 1
     preserve_srcdir = True
 
     def setup(self):
         os.chdir(self.srcdir)
-        utils.system('make clean')
-        utils.system('make')
+        utils.make('clean')
+        utils.make()
 
     def run_once(self, num_iteration = -1, test_list = ''):
         exefile = os.path.join(self.srcdir, 'hardware_MemoryThroughput')
         cmd = '%s %d %s' % (exefile, num_iteration, test_list)
         self.results = utils.system_output(cmd, retain_output = True)
 
         # Resulting time in MicroSec / MegaBytes.
         # Write out memory operation performance in MegaBytes / Second.
         performance_pattern = re.compile(
             r"Action = ([a-z0-9.]+), BlockSize = (\w+), " +
             r"Method = (\w+), Time = ([0-9.]+)")
         keyval_list = performance_pattern.findall(self.results)
         keyvals = {}
         for keyval in keyval_list:
             key = ('mb_per_sec_memory_' +
                    keyval[0] + '_' + keyval[1] + '_' + keyval[2])
             keyvals[key] = 1000000.0 / float(keyval[3])
         self.write_perf_keyval(keyvals)
 
         # Detect if an error has occured during the tests.
         # Do this after writing out the test results so even an error occurred,
         # we still get the performance evaluation.
         error_pattern = re.compile(r"ERROR: \[(.+)\]")
         errors = error_pattern.findall(self.results)
         if len(errors) > 0:
             logging.debug(self.results)
             raise error.TestFail('malfunctioning memory detected');