Detect invalid arch specific properties in snapshot

Previously, the snapshot code did not know whether a specific property
could be arch specific or not and assumed that they all were which
meant that it could generate snapshots containing arch specific values
for properties that are not arch specific and so would fail when
unpacked.

This change requires arch specific fields in SdkMemberProperties to be
tagged as such using `android:"arch_variant"` (just as in module input
property structures). Any property without that must have properties
that are common across all variants.

Bug: 155628860
Test: m nothing
Change-Id: Ifc8116e11d987cfe7aec2eeaa964f3bbf36b5dc2