Exclude non-triple-term comparisons from op-4

As discussed in #168, <= and >= are not defined on IRIs and blank nodes
in the SPARQL operator table.
As such, this spec test should not rely on their existence,
even though some implementations may have support for them through
operator extensions.

Author: rubensworks

sparql/sparql12/eval-triple-terms/op-4.rq

@@ -3,6 +3,7 @@ PREFIX :       <http://example/>
 SELECT * {
   ?x :left ?left .
   ?x :right ?right .
+  FILTER ( isTRIPLE(?left) && isTRIPLE(?right) )
   FILTER ( ?left <= ?right )
   FILTER ( ?right >= ?left )
 }

sparql/sparql12/eval-triple-terms/op-4.srj

@@ -285,34 +285,6 @@
                     },
                     "type": "triple"
                 }
-            },
-            {
-                "x": {
-                    "value": "http://example/x9",
-                    "type": "uri"
-                },
-                "left": {
-                    "value": "http://example/irireifier",
-                    "type": "uri"
-                },
-                "right": {
-                    "value": "http://example/irireifier",
-                    "type": "uri"
-                }
-            },
-            {
-                "x": {
-                    "value": "http://example/x10",
-                    "type": "uri"
-                },
-                "left": {
-                    "value": "bc_0_b0_bnodereifier",
-                    "type": "bnode"
-                },
-                "right": {
-                    "value": "bc_0_b0_bnodereifier",
-                    "type": "bnode"
-                }
             }
         ]
     }