resourceloader: Deprecate mw.Map

resourceloader: Deprecate mw.Map

This has never been used outside mediawiki.js for things like mw.config,
and mw.messages.

The public API of those objects will remain, but the constructor will
no longer be supported in the future in order to allow these to be
backed by native Map in the future (with a minimal polyfill rather than
a complete one).

* Remove 'mw.Map(valuesObject)'. (follows-up 63f8d7b9e5).
  This is incompatible with native Map and isn't actually used anywhere.

* Deprecate mw.Map#values. Undocumented and considered private.
  A few uses have appeared in the wild so keep a short deprecation period.

* Update the MediaWiki QUnit runner to construct new maps in setup/teardown
  instead of swapping the internal values object directly.
  Also update the runner to update mediawiki.jqueryMsg's parser default since
  it kept a reference to the first mw.messages object.

* Add 'logName' parameter to mw.log.deprecate(). Default logName
  of property key made sense for its original use case (deprecation warnings
  for global variables, which are a property of the window object). But
  for keys of any other object, we'll want to some context for the name.

* Remove redundant test expect numbers. (Follows-up 7c36375, c4c7007d)

* Ensure mw.Map.prototype.constructor points to mw.Map.
  This was broken by 5819c37b3, which accidentally made it point to Object.

Bug: T146432
Change-Id: I7ff0b230608f5ca582fc6752b59c4bb998c78ba2