NNAPI VTS: Add validation for Priority

This CL also cleans up the validation framework code.

Bug: 67828197
Test: mma
Test: VtsHalNeuralnetworksV1_*TargetTest
Change-Id: I84661fb2b8204148788d10425ca0ac986158b15f
diff --git a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
index 05eefd1..0baa85b 100644
--- a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
+++ b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
@@ -24,15 +24,17 @@
 
 using implementation::ExecutionCallback;
 
+using ExecutionMutation = std::function<void(Request*)>;
+
 ///////////////////////// UTILITY FUNCTIONS /////////////////////////
 
 // Primary validation function. This function will take a valid request, apply a
 // mutation to it to invalidate the request, then pass it to interface calls
-// that use the request. Note that the request here is passed by value, and any
-// mutation to the request does not leave this function.
+// that use the request.
 static void validate(const sp<IPreparedModel>& preparedModel, const std::string& message,
-                     Request request, const std::function<void(Request*)>& mutation) {
-    mutation(&request);
+                     const Request& originalRequest, const ExecutionMutation& mutate) {
+    Request request = originalRequest;
+    mutate(&request);
     SCOPED_TRACE(message + " [execute]");
 
     sp<ExecutionCallback> executionCallback = new ExecutionCallback();