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/esprima/es2015-array-pattern/with-object-pattern/expected.json

@@ -116,7 +116,8 @@
                           "end": {
                             "line": 1,
                             "column": 7
-                          }
+                          },
+                          "identifierName": "a"
                         },
                         "name": "a"
                       },
@@ -132,9 +133,13 @@
                           "end": {
                             "line": 1,
                             "column": 7
-                          }
+                          },
+                          "identifierName": "a"
                         },
                         "name": "a"
+                      },
+                      "extra": {
+                        "shorthand": true
                       }
                     }
                   ]