Move the guard definition ENABLE_VENDOR_CLUSTER_PROPERTY_FOR_TESTING.

- The target code is compiled with the libary, so move the definition
  to the libary.

Bug: 181802283
Test: check if ClusterOSDouble gets the vendor messages.

Change-Id: Id501be674844bda73ccf5ae74d97a363869db7b7

automotive/vehicle/2.0/default/Android.bp

@@ -78,6 +78,7 @@ cc_library_static {
     name: "android.hardware.automotive.vehicle@2.0-default-impl-lib",
     vendor: true,
     defaults: ["vhal_v2_0_target_defaults"],
+    cflags: ["-DENABLE_VENDOR_CLUSTER_PROPERTY_FOR_TESTING"],
     srcs: [
         "impl/vhal_v2_0/CommConn.cpp",
         "impl/vhal_v2_0/EmulatedVehicleConnector.cpp",
@@ -210,7 +211,6 @@ cc_binary {
     vendor: true,
     relative_install_path: "hw",
     srcs: ["VehicleService.cpp"],
-    cflags: ["-DENABLE_VENDOR_CLUSTER_PROPERTY_FOR_TESTING"],
     shared_libs: [
         "libbase",
         "libjsoncpp",