binder: optimize OnewayCallQueueing

    time out/host/linux-x86/nativetest64/binderRpcTestNoKernel/binderRpcTestNoKernel --gtest_filter="*OnewayCallQueueing*"

    before: 1:20.09 total
    after: 49.387 total

All of the time is spent in saturateThreadPool now.

Bug: 271860373
Test: see above
Change-Id: Id41ff1d6e77070c39c656c07be87028011c6e663
diff --git a/libs/binder/tests/binderRpcTestService.cpp b/libs/binder/tests/binderRpcTestService.cpp
index a27bd2f..ca5a117 100644
--- a/libs/binder/tests/binderRpcTestService.cpp
+++ b/libs/binder/tests/binderRpcTestService.cpp
@@ -83,6 +83,18 @@
         fd->reset(mFdChannel.read());
         return Status::ok();
     }
+
+    HandoffChannel<int> mIntChannel;
+
+    Status blockingSendIntOneway(int n) override {
+        mIntChannel.write(n);
+        return Status::ok();
+    }
+
+    Status blockingRecvInt(int* n) override {
+        *n = mIntChannel.read();
+        return Status::ok();
+    }
 };
 
 int main(int argc, char* argv[]) {