fix anr when concurrent request provider

anr reason:
1. system_server process: each binder thread is  waiting for provider publish,
so there is no idle binder thread;
2. providerTest process: process which contains target provider
 is publishing Content Provider, so binder call to system_server,
but no idle binder thread in system_server.

details as below:
https://code.google.com/p/android/issues/detail?id=239971



Test: using providerTest.apk can reproduct anr issue

Change-Id: I6a759a36b5a73a04bc884e56ad2abb6f8173312d
Signed-off-by: yuanhuihui <yuanhuihui@xiaomi.com>