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

[ROCm/rccl commit: fee1a20b74]
2020-06-09 17:44:15 -07:00
@@ -115,5 +115,6 @@ namespace CorrectnessTests
                                // Number of devices
                                testing::Values(2,3,4),
                                // In-place or not
-                                testing::Values(false, true)));
+                                testing::Values(false, true),
+                                testing::Values("")));
 } // namespace