Add JNI method to skip epoll_wait if possible

This change adds a flag for skipping epoll_wait when possible, which is
propagated to the native looper. This is flagged here instead of in the
looper implementation because libutils is not flaggable.

Test: atest MessageQueueTest
Bug: 410218466
Flag: android.os.native_looper_skip_epoll_wait_for_zero_timeout
Change-Id: I02a5293480b3d9022d75723423358ab24f8b0b0b