Address data race(s) seen in an engine_testapp's mock_server API: mock_get_current_time()

10:36:54 WARNING: ThreadSanitizer: data race (pid=83909)

10:36:54   Write of size 4 at 0x0000014d5640 by thread T9:

10:36:54     #0 mock_get_current_time /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/memcached/programs/engine_testapp/mock_server.c (engine_testapp+0x0000004ce90f)

10:36:54     #1 ExecutorThread::run() /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/ep-engine/src/executorthread.cc:100 (ep.so+0x0000001e374c)

10:36:54     #2 launch_executor_thread(void*) /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/ep-engine/src/executorthread.cc:34 (ep.so+0x0000001e2efa)

10:36:54     #3 platform_thread_wrap /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/platform/src/cb_pthreads.c (libplatform.so.0.1.0+0x0000000036ac)

10:36:54 

10:36:54   Previous write of size 4 at 0x0000014d5640 by thread T8:

10:36:54     #0 mock_get_current_time /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/memcached/programs/engine_testapp/mock_server.c (engine_testapp+0x0000004ce90f)

10:36:54     #1 ExecutorThread::run() /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/ep-engine/src/executorthread.cc:100 (ep.so+0x0000001e374c)

10:36:54     #2 launch_executor_thread(void*) /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/ep-engine/src/executorthread.cc:34 (ep.so+0x0000001e2efa)

10:36:54     #3 platform_thread_wrap /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/platform/src/cb_pthreads.c (libplatform.so.0.1.0+0x0000000036ac)

10:36:54 

10:36:54 WARNING: ThreadSanitizer: data race (pid=83935)

10:36:54   Write of size 4 at 0x0000014d5668 by main thread:

10:36:54     #0 mock_time_travel <null> (engine_testapp+0x0000004cdf83)

10:36:54     #1 test_memory_limit(engine_interface*, engine_interface_v1*) /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/ep-engine/tests/ep_testsuite.cc:2590 (ep_testsuite.so+0x000000023fd1)

10:36:54     #2 execute_test /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/memcached/programs/engine_testapp/engine_testapp.c (engine_testapp+0x0000004c4e9f)

10:36:54     #3 main crtstuff.c (engine_testapp+0x0000004c2e01)

10:36:54 

10:36:54   Previous read of size 4 at 0x0000014d5668 by thread T9:

10:36:54     #0 mock_get_current_time /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/memcached/programs/engine_testapp/mock_server.c (engine_testapp+0x0000004ce8e8)

10:36:54     #1 ExecutorThread::run() /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/ep-engine/src/executorthread.cc:100 (ep.so+0x0000001e374c)

10:36:54     #2 launch_executor_thread(void*) /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/ep-engine/src/executorthread.cc:34 (ep.so+0x0000001e2efa)

10:36:54     #3 platform_thread_wrap /home/couchbase/jenkins/workspace/ep-engine-threadsanitizer-3.0.x/platform/src/cb_pthreads.c (libplatform.so.0.1.0+0x0000000036ac)