add ds_8streams.json (#48)

Author: yabinma

benchmarks/tpc-ds/ds_8streams.json

@@ -0,0 +1,13 @@
+{
+  "description": "Run the first 8 parallel queries streams defined in the TPC-DS spec Appendix D: Query Ordering. See stream_gen_test.go.",
+  "next": [
+    "streams/stream_01.json",
+    "streams/stream_02.json",
+    "streams/stream_03.json",
+    "streams/stream_04.json",
+    "streams/stream_05.json",
+    "streams/stream_06.json",
+    "streams/stream_07.json",
+    "streams/stream_08.json"
+  ]
+}