tests: Fix trace-cmd output for host case

Both the output file path and the current working directory included the
log directory and this failed if log directory was not absolute (e.g.,
when using the default logs/current in the case a VM is not used).

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

tests/hwsim/run-tests.py

@@ -101,7 +101,7 @@ class DataCollector(object):
         self._dmesg = dmesg
     def __enter__(self):
         if self._tracing:
-            output = os.path.join(self._logdir, '%s.dat' % (self._testname, ))
+            output = os.path.abspath(os.path.join(self._logdir, '%s.dat' % (self._testname, )))
             self._trace_cmd = subprocess.Popen(['sudo', 'trace-cmd', 'record', '-o', output, '-e', 'mac80211', '-e', 'cfg80211', 'sh', '-c', 'echo STARTED ; read l'],
                                                stdin=subprocess.PIPE,
                                                stdout=subprocess.PIPE,