Multi stream unit test (#693)

* Adding multi-stream support to unit tests

test/common/CollectiveArgs.cpp

@@ -16,6 +16,7 @@ namespace RcclUnitTesting
                                   ncclDataType_t  const  dataType,
                                   size_t          const  numInputElements,
                                   size_t          const  numOutputElements,
+                                  int             const  streamIdx,
                                   OptionalColArgs const  &optionalColArgs)
   {
     // Free scalar based on previous scalarMode
@@ -35,6 +36,7 @@ namespace RcclUnitTesting
     this->dataType          = dataType;
     this->numInputElements  = numInputElements;
     this->numOutputElements = numOutputElements;
+    this->streamIdx         = streamIdx;
     this->options           = optionalColArgs;
 
     if (this->options.scalarMode != -1)