Reduce LocationManager memory usage

Move GNSS listener overhead into statics so it's shared per process, and
do not instantiate by default.

Previously GNSS requests were multiplexed by LocationManager instance,
this is now removed. This could mean additional binder overhead, but
it's pretty unlikely that this feature was in active use anywhere, as in
any large application that has multiple gnss requests, they are usually
coming from different contexts (and thus LocationManager instances) and
would not have seen the benefit of multiplexing anyways.

Bug: 179261871
Test: atest CtsLocationFineTestCases
Change-Id: I8b7a41c13dfe219c326b1e519483d89d2b721ce5