Implement keepAliveBinder for setRpcClientDebug

setRpcClientDebug can now be called multiple times. Each will
set up a different RpcServer and opens up a different port.

When keepAliveBinder dies, the corresponding RpcServer also
dies.

Also fixes tests to meet new expectations.
- Positive tests now only run on remote binder, because the
  keepAliveBinder object cannot be a local binder to call
  linkToDeath.
- Negative tests keeps running on local and remote binders.
- Use real servicedispatcher.

Test: binderLibTest
Test: manual with servicedispatcher.

Bug: 182914638

Change-Id: Ic46ac54bb7988ee7d65546563f56f0a02c29ce7c