autotests: Reduce execution time of testLockScreen
testLockScreen uses !eventSpy.wait() expression to check whether the given signal is emitted. QSignalSpy::wait()'s default timeout is 5s, which is too much. We don't need to wait that much, in fact, even wl_display_sync() would suffice. In either case, let's pass explicit timeout of 10ms which should be good enough.
Before
Executed in 60.49 secs fish external
usr time 3.92 secs 1.03 millis 3.92 secs
sys time 2.29 secs 0.16 millis 2.29 secs
After
Executed in 19.38 secs fish external
usr time 1.64 secs 347.00 micros 1.64 secs
sys time 1.15 secs 54.00 micros 1.15 secs