[SYCL][UR] Use static cast instead of ur::cast (#14830)

UR cast is using reinterpret cast under the hood, which was failing for
an
unsigned long being cast to an unsigned long long. From the C++ spec:

> An expression of integral, enumeration, pointer, or pointer-to-member 
type can be converted to its own type. The resulting value is the same
as
the value of expression.

Since `unsigned long` is not the same type as `unsigned long long`, the
`reinterpret_cast` fails.

Ping @aarongreig

Author: Hugh Delaney

sycl/include/sycl/backend.hpp

@@ -96,7 +96,7 @@ struct BufferInterop {
   GetNativeObjs(const std::vector<ur_native_handle_t> &Handle) {
     ReturnType ReturnValue = 0;
     if (Handle.size()) {
-      ReturnValue = detail::ur::cast<ReturnType>(Handle[0]);
+      ReturnValue = (ReturnType)(Handle[0]);
     }
     return ReturnValue;
   }

sycl/test-e2e/EnqueueNativeCommand/custom-command-cuda.cpp

@@ -2,9 +2,6 @@
 // RUN: %{run} %t.out
 // REQUIRES: cuda, cuda_dev_kit
 
-// TODO: Reenable, see https://github.com/intel/llvm/issues/14598
-// UNSUPPORTED: windows, linux
-
 #include <cuda.h>
 
 #include <iostream>

sycl/test-e2e/EnqueueNativeCommand/custom-command-multiple-dev-cuda.cpp

@@ -2,9 +2,6 @@
 // RUN: %{build} -o %t.out %cuda_options
 // RUN: %{run} %t.out
 
-// TODO: Reenable, see https://github.com/intel/llvm/issues/14598
-// UNSUPPORTED: windows
-
 #include <cuda.h>
 
 #include <iostream>