Index-only plan step 2: Added SplitOperator

 - Introduced SplitOperator that sends a tuple to only one output frame unlike the ReplicateOperator
   that propagates a tuple into all outputs frames.
 - Removed PartitioningSplitOperator and PartitioningSplitOperatorDescriptor that are not functional
   (lacking physical operator)
 - Added a unit test case of SplitOperatorDescriptor in PushRuntimeTest.

Change-Id: Ice190827513cd8632764b52c9d0338d65c830740
Reviewed-on: https://asterix-gerrit.ics.uci.edu/1196
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Yingyi Bu <buyingyi@gmail.com>
diff --git a/hyracks-fullstack/algebricks/algebricks-tests/data/simple/int-string-part1.tbl b/hyracks-fullstack/algebricks/algebricks-tests/data/simple/int-string-part1.tbl
new file mode 100644
index 0000000..ceb859a
--- /dev/null
+++ b/hyracks-fullstack/algebricks/algebricks-tests/data/simple/int-string-part1.tbl
@@ -0,0 +1,7 @@
+0|first branch1
+1|second branch1
+0|first branch2
+1|second branch2
+0|first branch3
+1|second branch3
+0|first branch4
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