Don't freeze bindee process if bound with BIND_ALLOW_OOM_MANAGEMENT

Also fixed app freezer's settings change observer, added a device
config item for the debounce timeout, as well as a lock ordering issue

Bug: 183735766
Test: atest FrameworksServicesTests:ActivityManagerTest
Test: atest CachedAppOptimizerTest
Change-Id: Idfdc90fd55172103eb6bb1ab1f64e5c4f17c89c3