gtest: add scatter, gather and all to all unit tests

test/test_AllReduceAbort.cpp

@@ -138,5 +138,6 @@ namespace CorrectnessTests
                                 // Number of devices
                                 testing::Values(2, 4),
                                 // In-place or not
-                                testing::Values(false)));
+                                testing::Values(false),
+                                testing::Values("")));
 } // namespace