Merge the "Given the test page has been created" and "Given I am on the
... page" as they are only ever used together to mean "Given I am on the
test page".
Supporting changes:
* samples/links.wikitext -> fixtures/test_page.wikitext as it's more
obvious what the file is.
Change-Id: Ide261a8e8c55133ab2a13a80c48e266252f61f5f
