[SYCL] Use sycl/detail/core.hpp in test-e2e/UserDefinedReductions/* (#13841)

Continuation of changes started in
#12890.

Author: aelovikov-intel

sycl/include/sycl/ext/oneapi/experimental/user_defined_reductions.hpp

@@ -9,6 +9,7 @@
 #pragma once
 
 #include <sycl/detail/defines.hpp>
+#include <sycl/ext/oneapi/experimental/group_helpers_sorters.hpp>
 #include <sycl/group_algorithm.hpp>
 
 namespace sycl {

sycl/test-e2e/UserDefinedReductions/user_defined_reductions.cpp

@@ -4,8 +4,8 @@
 #include <complex>
 #include <numeric>
 
+#include <sycl/detail/core.hpp>
 #include <sycl/ext/oneapi/experimental/user_defined_reductions.hpp>
-#include <sycl/sycl.hpp>
 
 template <typename T> struct UserDefinedSum {
   T operator()(T a, T b) { return a + b; }

sycl/test-e2e/UserDefinedReductions/user_defined_reductions_wg_size_larger_than_data_size.cpp

@@ -4,8 +4,8 @@
 #include <iostream>
 #include <numeric>
 
+#include <sycl/detail/core.hpp>
 #include <sycl/ext/oneapi/experimental/user_defined_reductions.hpp>
-#include <sycl/sycl.hpp>
 
 // 1. Allocate an buffer of 16 elements where first 8 elements filled with 1,
 //    ..., 8 and the second 8 elements filled with 0.