libbinder : Avoid waiting in binder_rpc_fuzzer

Introducing new APIs in RpcServer and RpcSession to check
polling state of file descriptor. Removing fixed wait time
in binder_rpc_fuzzer.

Test: m binder_rpc_fuzzer &&
$ANDROID_HOST_OUT/fuzz/x86_64/binder_rpc_fuzzer/binder_rpc_fuzzer
Bug: 218518615

Change-Id: Ied82cd9c16514761a489731488924274a17053a6