gtest: extend testing up to 8 GPUs

[ROCm/rccl commit: 8db0aa8f4c]

projects/rccl/test/test_ReduceScatter.cpp

@@ -59,9 +59,9 @@ namespace CorrectnessTests
                                                 ncclFloat64,
                                                 ncclBfloat16),
                                 // Number of elements
-                                testing::Values(3072, 3145728),
+                                testing::Values(2520, 3026520),
                                 // Number of devices
-                                testing::Values(2,3,4),
+                                testing::Values(2,3,4,5,6,7,8),
                                 // In-place or not
                                 testing::Values(false, true),
                                 testing::Values("")));