Validate that setSuiteProperty and setSpecProperty args are cloneable

src/core/Spec.js

@@ -70,8 +70,12 @@ getJasmineRequireObj().Spec = function(j$) {
       return this.result.properties[key];
     }
 
-    // TODO: throw if the key or value is not structred cloneable
     setSpecProperty(key, value) {
+      // Key and value will eventually be cloned during reporting. The error
+      // thrown at that point if they aren't cloneable isn't very helpful.
+      // Throw a better one now.
+      j$.util.assertStructuredCloneable(key, 'Key');
+      j$.util.assertStructuredCloneable(value, 'Value');
       this.result.properties = this.result.properties || {};
       this.result.properties[key] = value;
     }