Reorganize fuzz tests to use injectArbitrary

Have each test fixture do it's own arbitrary fuzzing
based on it's API surface, instead of requiring
fuzz tests themselves to know what the surface is
and keep up to date.

This will allow us to reuse test fixtures in multiple
fuzz tests without needing to manually keep all of them
up to date with surface changes.

Test: fuzz/run --host bluetooth_gd_acl_manager_fuzz_test
Test: fuzz/run --host bluetooth_gd_hci_layer_fuzz_test
Change-Id: Ibf4958fecc98fdf1f6526b0439a36d69b0f6286e