cmd+tester: Parameterized tests (#7366)

Adding the ability to parameterize Rego `test_*` rules, effectively declaring multiple "test cases" within the rule, which is then individually reported (grouped under their parent rule) when running `opa test`.

Fixes: #2176

Signed-off-by: Johan Fylling <johan.dev@fylling.se>

capabilities.json

@@ -1617,6 +1617,20 @@
         "type": "function"
       }
     },
+    {
+      "name": "internal.test_case",
+      "decl": {
+        "args": [
+          {
+            "dynamic": {
+              "type": "any"
+            },
+            "type": "array"
+          }
+        ],
+        "type": "function"
+      }
+    },
     {
       "name": "intersection",
       "decl": {