Add __hip_pinned_shadow__ for hip-clang and fix texture reference tests (#1200)

tests/src/texture/hipTextureRef2D.cpp

@@ -9,6 +9,9 @@
 
 #include <hip/hip_runtime.h>
 #include "test_common.h"
+#if __HIP__
+__hip_pinned_shadow__
+#endif
 texture<float, 2, hipReadModeElementType> tex;
 
 __global__ void tex2DKernel(float* outputData,