[ABI-Break][SYCL] Enforce buffer's element type to be device copyable (#13200)

Author: aelovikov-intel

sycl/include/sycl/buffer.hpp

@@ -167,13 +167,8 @@ template <typename T, int dimensions = 1,
               typename std::enable_if_t<(dimensions > 0) && (dimensions <= 3)>>
 class buffer : public detail::buffer_plain,
                public detail::OwnerLessBase<buffer<T, dimensions, AllocatorT>> {
-#ifdef __INTEL_PREVIEW_BREAKING_CHANGES
   static_assert(is_device_copyable_v<T>,
                 "Underlying type of a buffer must be device copyable!");
-#else
-  static_assert(!std::is_same_v<T, std::string>,
-                "'std::string' is not a device copyable type");
-#endif
 
 public:
   using value_type = T;