This allows checking restrictions without a dependency on Title, based
only on a PageIdentity.
Additional fixes along the way:
* Correctly return false instead of 'infinity' for
getRestrictionExpiry( 'create' ) on an existing page
* Correctly handle non-special pages that can't exist (like media pages)
in listApplicableRestrictionTypes() (return empty array instead of
'create')
* Improve readability of isProtected()
The expectation change in TitleTest::testIsProtected() is because the
test was formerly broken, since it set mRestrictions without setting
mRestrictionsLoaded. (Which illustrates how this approach to testing is
essentially broken.)
Co-authored-by: Vedmaka <god.vedmaka@gmail.com>
Bug: T218395
Change-Id: Ia73ea587586cb69eb53265b2f8f7a296a2573dd0
cf818256fb