AssetManager2: optionally keep non-matching configs

AssetManager2 maintains a set of configurations [as specified in the
resource blob] compatible with the currently set configuration [as
specified via SetConfiguration]. This helps optimize future resource
lookups by limiting the set of configurations to iterate over.

However, when creating idmaps, all configurations must be considered,
including those not compatible with the currently set configuration. Add
an optional flag to SetApkAssets to disable the optimization described
above.

Test: manual (will be tested by upcoming idmap2 implementation)
Change-Id: I7526a323ddf90e2f2f49c36e8c110a2cec25357e