Multiple fixes in ScrollView and HorizontalScrollView

* Fixes a bug in HSV where it was not using unspecified measurement hint
* Fixed a bug in SV where it was ignoring padding and margin when
specifying measurement hint.
* Fixes a bug in both where padding/margin were not taken into account
when re-mausing for fill viewport.
* Fixes a bug in both where the ViewGroup's padding was ignored when
measureChild is called.

Bug: 27602908
Change-Id: I15cb942e0fc2ef39c753ff35d36e1d007f4e05a8