binderThroughputTest: replace getService with waitForService

The getService() method is now deprecated, replace with waitForService()
which waits indefinitely instead of timing out. This should fix the
following compilation warning:

binderThroughputTest.cpp:207:39: warning: 'getService' is deprecated: this polls for 5s, prefer waitForService or checkService [-Wdeprecated-declarations]
        workers.push_back(serviceMgr->getService(generateServiceName(i)));
                                      ^
frameworks/native/libs/binder/include/binder/IServiceManager.h:70:7: note: 'getService' has been explicitly marked deprecated here
    [[deprecated("this polls for 5s, prefer waitForService or checkService")]]
      ^
1 warning generated.

Change-Id: Ib6721b355a5fe7e79d9b8c6949b54e3eb49f237f
Signed-off-by: Carlos Llamas <cmllamas@google.com>
[ Alice: Fix conflict with commit bb07b983 ("Fix or silence binder
  build warnings on clang"). ]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>