Clean up location flags

The list of "Flag name: original CL":

release_supl_connection_on_timeout: ag/25697061
location_validation: ag/25532617
replace_future_elapsed_realtime_jni: ag/25756176
use_legacy_ntp_time: ag/29483929
subscriptions_changed_listener_thread: ag/26990464
enable_ni_supl_message_injection_by_carrier_config: ag/29421068 (note that this flag is renamed so it's not used in any code)

Bug: 409606054
Bug: 409606465
Bug: 409605197
Bug: 409604889
Bug: 409606483
Test: atest LocationProviderManagerTest
Flag: EXEMPT removing release_supl_connection_on_timeout, location_validation, replace_future_elapsed_realtime_jni, use_legacy_ntp_time, subscriptions_changed_listener_thread,  enable_ni_supl_message_injection_by_carrier_config
Change-Id: I481c7369b6c154954d56d94a92df18b8383ed9e7