Converting ptrdiff_t type to int64_t type in cxx11_tensor_contract_sycl.cpp in order to be the same as other tests.
Converting ptrdiff_t type to int64_t type in cxx11_tensor_contract_sycl.cpp in order to be the same as other tests.

pthulhu/eigen,pthulhu/eigen,pthulhu/eigen,pthulhu/eigen,pthulhu/eigen