Implement per-test timeout guard

Timeout value can be specified by test in suite.conf:

config:
  suite:
    <suite_name>:
      <test_name>:
        timeout: 2 # 2 seconds timeout

Change-Id: I522f51f77f8be64ebfdb5d5e07ba92baf82d7706
diff --git a/selftest/suite_test/suitedirA/test_suite/test_timeout.py b/selftest/suite_test/suitedirA/test_suite/test_timeout.py
new file mode 100644
index 0000000..eeddb70
--- /dev/null
+++ b/selftest/suite_test/suitedirA/test_suite/test_timeout.py
@@ -0,0 +1,6 @@
+from osmo_gsm_tester.testenv import *
+
+timeout = int(tenv.config_test_specific()['timeout'])
+print('starting test and waiting to receive Timeout after %d seconds' % timeout)
+sleep(10)
+print('test failed, we expected timeout after %d seconds' % timeout)