Forth: additional tests for "combined arithmetic" category

This will ensure that students are popping numbers off the correct end of the stack (for languages without a builtin Stack type).

Author: glennj

exercises/forth/canonical-data.json

@@ -213,6 +213,24 @@
             "instructions": ["2 4 * 3 /"]
           },
           "expected": [2]
+        },
+        {
+          "uuid": "",
+          "description": "multiplication and addition",
+          "property": "evaluate",
+          "input": {
+            "instructions": ["1 3 4 * +"]
+          },
+          "expected": [13]
+        },
+        {
+          "uuid": "",
+          "description": "addition and multiplication",
+          "property": "evaluate",
+          "input": {
+            "instructions": ["1 3 4 + *"]
+          },
+          "expected": [7]
         }
       ]
     },