Replace get_select_option with Selenium's native select_by_value

[Johannes Maron]

We have our own method called django.contrib.admin.tests.AdminSeleniumTestCase.get_select_option which does the very same thing as selenium.webdriver.support.select.Select.select_by_value.

We could replace it with something like:

def select_option(self, select_tag_css_selector, value):
    from selenium.webdriver.support.ui import Select

    select = Select(self.selenium.find_element_by_css_selector(select_tag_css_selector))
    select.select_by_value(value)

This would avoid looping over the DOM-tree as it's done in the current implementation.
Furthermore, it can avoid errors when a select-tag is outside the current viewport.

[Carlton Gibson]

OK. Sounds good. — Thanks again! (Will review all three tickets next week.)

[Carlton Gibson <carlton.gibson@…>]

In 249a6190:

Fixed #30975 -- Replaced custom get_select_option with Selenium's select_by_value.