Fixed tests on group by

com.oracle.truffle.r.test/tests/hbase/QueryGroup.R

@@ -3,7 +3,7 @@ q = groupby(function (x) c(x$deptno),
     select(function (x) {
              res = new.env()
              res$deptno = x$deptno
-             res$sum = sum(x$sal)
+             res$sumSal = sum(x$sal)
              res },
     from(emp)))
 results = query.force(q)

com.oracle.truffle.r.test/tests/hbase/QueryGroup.out

-  deptno   sum
-1      1  4047
-2      3 13356
-3      2 15810
+  sumsal deptno
+1   4047      1
+2  13356      3
+3  15810      2
 

com.oracle.truffle.r.test/tests/pgsql/QueryGroup.R

@@ -3,7 +3,7 @@ q = groupby(function (x) c(x$deptno),
     select(function (x) {
              res = new.env()
              res$deptno = x$deptno
-             res$sum = sum(x$sal)
+             res$sumSal = sum(x$sal)
              res },
     from(emp)))
 results = query.force(q)

com.oracle.truffle.r.test/tests/pgsql/QueryGroup.out

-  deptno   sum
-1      1  4047
-2      3 13356
-3      2 15810
+  sumsal deptno
+1   4047      1
+2  13356      3
+3  15810      2