[DX][HttpFoundation] Allow to check multiple methods at once

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

This code allows to replace calls like:
```php
if (in_array($request->getMethod(), array('POST', 'PUT', 'PATCH'))) {
    // do something
}
```
With:
```php
if ($request->isMethod(array('POST', 'PUT', 'PATCH'))) {
    // do something
}
Good point. Isn't explicitly allowed by the doc comment, though. Not sure how symfony handles implicit conversions via `__toString` (i.e. whether this would be a BC break).

If it is:
```php
$method = is_object($m) ? (string) $m : $m;

foreach ((array) $method as $m) {
    if ($this->getMethod() === strtoupper($m)) {
        return true;
    }
}

return false;
```

Would still keep it in separate lines, for the sake of readability.