Revert "Revert "Testing AIDL delegator class with RPC""

This reverts commit 2fcd479e87ce8b1251ab64943250f0e36e9f8ac3.

The original commit was submitted with the system/tools/aidl commit that
broke the build.
That commit is fixed with the revert of the revert.
So this revert is being reverted..

Test: atest binderRpcTest
Bug: 198785815
Change-Id: I6f3fc85c9398801f7db0c81c8874d4c27dc36055
diff --git a/libs/binder/tests/binderRpcTest.cpp b/libs/binder/tests/binderRpcTest.cpp
index 8267702..f132ff7 100644
--- a/libs/binder/tests/binderRpcTest.cpp
+++ b/libs/binder/tests/binderRpcTest.cpp
@@ -1307,6 +1307,16 @@
     ASSERT_EQ(beforeFds, countFds()) << (system("ls -l /proc/self/fd/"), "fd leak?");
 }
 
+TEST_P(BinderRpc, AidlDelegatorTest) {
+    auto proc = createRpcTestSocketServerProcess({});
+    auto myDelegator = sp<IBinderRpcTestDelegator>::make(proc.rootIface);
+    ASSERT_NE(nullptr, myDelegator);
+
+    std::string doubled;
+    EXPECT_OK(myDelegator->doubleString("cool ", &doubled));
+    EXPECT_EQ("cool cool ", doubled);
+}
+
 static bool testSupportVsockLoopback() {
     // We don't need to enable TLS to know if vsock is supported.
     unsigned int vsockPort = allocateVsockPort();