Add a test for boolean comparison.

js/test_cases/helpers_gt/input1.json

@@ -3,5 +3,7 @@
   "int": 7,
   "alpha": 21,
   "beta": "21",
-  "null": null
+  "null": null,
+  "true_value": true,
+  "false_value": false
 }

js/test_cases/helpers_gt/main.dust

@@ -21,3 +21,4 @@ beta is {beta}{~n}
 {@gt key="a" value="A"}"a" is greater than "A"{:else}"a" is less than or equal to "A"{/gt}{~n}
 {@gt key="a" value="}"}"a" is greater than "}"{:else}"a" is less than or equal to "}"{/gt}{~n}
 {@gt key="☃" value="☄"}"☃" is greater than "☄"{:else}"☃" is less than or equal to "☄"{/gt}{~n}
+{@gt key=true_value value=false_value}true is greater than false{:else}true is less than or equal to false{/gt}{~n}