urlLocaleKey - problem

```
intl.determineLocale({
urlLocaleKey: "lang"
});
```
i use react-router hashHistory
url-example-A(standard): `http://www.xxx.com/index.html?lang=en#/test`
url-example-B(non-standard): `http://www.xxx.com/index.html#/test?lang=en`

url-example-A：
```
window.location.search == '?lang=en'
window.location.hash == '#/test'
```

url-example-B：
```
window.location.search == ''
window.location.hash == '#/test?lang=en'
```

urlLocaleKey only stand by standard-URL ，can u stand by non-standard-URL like "http://www.xxx.com/index.html#/test?lang=en"

Start by locating the urlLocaleKey handling in the repository and inspect how window.location.search and window.location.hash are read. Add coverage for both URL examples, with the non-standard hash query resolving the locale as en when the lang key is present.

Written by the indexing model from the issue text.