Restrict dumping of binder proxy info in bugreports.

This dumping is done with the ActivityManagerService lock held, and
can take a while. Therefore, do the dumping without the lock, and
only dump proxy interface counts if the number of proxies looks
unreasonable to start with.

Bug: 119616995
Test: boots, bugreport doesn't dump proxy interfaces with normal count
Change-Id: If7ca8fbe08362db2ef57bf2e210160f37859fd79