[SYCL][E2E][NFC] Remove obsolete shuffles.hpp from subgroups tests (#14649)

The only test cases using `test-e2e/SubGroup/shuffle.hpp` was deleted in
#13236, so this is no longer needed. Either way, the header references
the `sub_group.shuffle` function, which no longer exists in intel/llvm
anyway.

Author: ianayl