Do not quote JSX attribute keys for IdentifierName (#8045)

Given the following

```js
a = <F new/>
```

We used to generate:

```js
a = React.createElement(F, {"new": true})
```

but now we generate

```js
a = React.createElement(F, {new: true})
```

If you need to quote these (ie for ES3 you can use
transform-property-literals)

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-add-quotes-es3/input.js

@@ -0,0 +1 @@
+var es3 = <F aaa new const var default foo-bar/>;

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-add-quotes-es3/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["transform-react-jsx", "transform-property-literals"]
+}

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-add-quotes-es3/output.js

@@ -0,0 +1,8 @@
+var es3 = React.createElement(F, {
+  aaa: true,
+  "new": true,
+  "const": true,
+  "var": true,
+  "default": true,
+  "foo-bar": true
+});

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-not-add-quotes-to-identifier-names/input.js

@@ -0,0 +1 @@
+var e = <F aaa new const var default foo-bar/>;

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-not-add-quotes-to-identifier-names/output.js

@@ -0,0 +1,8 @@
+var e = React.createElement(F, {
+  aaa: true,
+  new: true,
+  const: true,
+  var: true,
+  default: true,
+  "foo-bar": true
+});