Add new SystemProperties.Handle interface

This new interface allows Java code to look up property values without
paying for the name->prop_info mapping and, in the case of looking up
scalars, without doing any allocation.

Bug: 140788621
Test: added tests
Test: atest FrameworksCoreSystemPropertiesTests
Change-Id: I46d12f62499e9e124fe9add588376d724b364d5d