The Bluedroid on-demand materializer, the neutral lookup helpers' host
tests, and the USE_BLE_GATT_SERVICE_TABLE define move here, next to
their first consumer (the neutral engine's table resolution and the
service_table codegen flag). One behavior fix rides along: hitting
MAX_DESCRIPTORS_PER_CHARACTERISTIC now fails the walk like every other
inconsistency instead of truncating the table silently.
Nothing in this PR emits USE_BLE_GATT_SERVICE_TABLE, so the Bluedroid
materializer, the neutral find_service/find_characteristic/find_cccd
helpers, their host tests, and the defines.h entry were scaffolding with
no caller here. They move to the PR that introduces their first
consumer. The contract op stays: get_service_table() keeps its {} stub
(the proxy streams in place).
J. Nick Koston