Multi stream unit test (#693)

* Adding multi-stream support to unit tests

test/common/TestBedChild.hpp

@@ -65,9 +65,10 @@ namespace RcclUnitTesting
     int rankOffset;                                     // Global rank offset for this child
     int numCollectivesInGroup;                          // # of collectives to run per group call
     bool useBlocking;                                   // RCCL communication with blocking or non-blocking option
+    int numStreamsPerGroup;                             // # of different streams allowed per group call
     std::vector<ncclComm_t> comms;                      // RCCL communicators for each rank
     std::vector<int> deviceIds;                         // Device IDs for each rank
-    std::vector<hipStream_t> streams;                   // Streams for executing collectives
+    std::vector<std::vector<hipStream_t>> streams;      // Streams for executing collectives
     std::vector<std::vector<CollectiveArgs>> collArgs;  // Info for each collective for each rank
 
     // Constructor