Consolidate NNAPI VTS utility code

This CL does additional NNAPI VTS test cleanup, including consolidating
duplicate functionality. Specifically, this CL:
* consolidates the createPreparedModel function, removing the duplicate
* consolidates the std::out ErrorStatus and DeviceStatus code into Utils
* changes non-null constant pointers to constant references
* removes redudant leading namespace specifiers (V1_0::, ::testing, etc.)
* makes the Valdiation tests free functions
* renames device to kDevice and mTestModel to kTestModel

Bug: N/A
Test: mma
Test: VtsHalNeuralnetworksV1_*TargetTest (with sample-all)
Change-Id: Ic401bb1f1760cc10384ac0d30c0c93409b63a9c7
diff --git a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
index d8f3e65..05eefd1 100644
--- a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
+++ b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
@@ -87,8 +87,7 @@
 
 ///////////////////////////// ENTRY POINT //////////////////////////////////
 
-void ValidationTest::validateRequest(const sp<IPreparedModel>& preparedModel,
-                                     const Request& request) {
+void validateRequest(const sp<IPreparedModel>& preparedModel, const Request& request) {
     removeInputTest(preparedModel, request);
     removeOutputTest(preparedModel, request);
 }