Encapsulate properties to be optimized in a container

This allows additional metadata to be associated with a set of
properties that will be used in a follow up change to filter
properties that are ignored in some variants (e.g. host variants).

Bug: 155628860
Test: m nothing
Merged-In: Ie83c1ffbb71fd5d7a08d350571dad3e3209b1431
Change-Id: Ie83c1ffbb71fd5d7a08d350571dad3e3209b1431
(cherry picked from commit f34f6d85)