Add test to the BpBinder::getBinderProxyCount

Bug: 298314844
Test: atest BinderLibTest#BinderProxyCount
Merged-In: I97bbb5b7560f36294718ce22015079bc4f96ba22
Change-Id: I97bbb5b7560f36294718ce22015079bc4f96ba22
1 file changed