Move converting constructor from _Float16 under macro guard. Refactor.

hipamd/tests/src/deviceLib/hipTestHalf.cpp

@@ -23,9 +23,9 @@ THE SOFTWARE.
  * HIT_END
  */
 
-#include <iostream>
 #include <hip/hip_fp16.h>
 #include "hip/hip_runtime.h"
+
 #include "test_common.h"
 
 #if __HIP_ARCH_GFX803__ || __HIP_ARCH_GFX900__ || __HIP_ARCH_GFX906__