Back out "folly: cmake: enable DistributedMutexTest.cpp"

Summary:
I only enabled this speculatively, but since it quite a heavyweight
test, it is timing out in the open source build, so let's turn it off again.

Reviewed By: lewissbaker

Differential Revision: D14817162

fbshipit-source-id: 343b021890974e5b92975bdfc7b4fa554d20a703

CMakeLists.txt

@@ -741,7 +741,6 @@ if (BUILD_TESTS)
     DIRECTORY synchronization/test/
       TEST baton_test SOURCES BatonTest.cpp
       TEST call_once_test SOURCES CallOnceTest.cpp
-      TEST distributed_mutex_test SOURCES DistributedMutexTest.cpp
       TEST lifo_sem_test SOURCES LifoSemTests.cpp
       TEST rw_spin_lock_test SOURCES RWSpinLockTest.cpp