Fix RecyclerView measure spec utility methods

This CL fixes two issues with RecyclerView.
* Its default measure spec method was ignoring the padding and
was also taking complete space when its spec is AT_MOST.

* Fixed the getSize method in LayoutManager where if the
spec is AT_MOST, it could be ignored if there is also a
mindWidth / minHeight.

Bug: 27376820
Change-Id: I5764970fa31268fd98effee0f7bf8b4fd5f0824d
2 files changed