Test runner: Detect extra property in 'actual' but not in 'expected'. (#407)

* Test runner: Detect extra property in 'actual' but not in 'expected'.

Also update all expected.json where this would result in errors.

* Include rmExpected.js script in case it is needed again

test/fixtures/experimental/function-sent/inside-generator/expected.json

@@ -54,12 +54,14 @@
             "end": {
               "line": 1,
               "column": 13
-            }
+            },
+            "identifierName": "foo"
           },
           "name": "foo"
         },
         "generator": true,
         "expression": false,
+        "async": false,
         "params": [],
         "body": {
           "type": "BlockStatement",
@@ -116,7 +118,8 @@
                     "end": {
                       "line": 2,
                       "column": 17
-                    }
+                    },
+                    "identifierName": "function"
                   },
                   "name": "function"
                 },
@@ -132,7 +135,8 @@
                     "end": {
                       "line": 2,
                       "column": 22
-                    }
+                    },
+                    "identifierName": "sent"
                   },
                   "name": "sent"
                 }