Update CachedProperty to support long ro. properties

We store a pointer to the long ro. property within the shared property
area, as we know that this pointer will never change locations or be
invalidated and it saves us from needing to allocate arbitrarily sized
storage for the property.

Bug: 23102347
Bug: 34954705
Test: bionic-unit-tests
Change-Id: I9f9147a2f951f20f51e4664c6faf9ff7f6a9502a