[SYCL][NFC] Remove get_device_count_by_type sources

[sergey-semenov]

This tool is not needed, we stopped building it a while back in #6706

[sergey-semenov]

HIP failures are unrelated:

lit.py: /__w/llvm/llvm/llvm/sycl/test-e2e/lit.cfg.py:4[23](https://github.com/intel/llvm/actions/runs/6086401693/job/16513420245?pr=11064#step:21:24): error: Cannot detect device aspect for ext_oneapi_hip:gpu
stdout:

Platforms: 0
default_selector()      : No device of requested type available. -1 (PI_ERRO...
accelerator_selector()  : No device of requested type available. -1 (PI_ERRO...
cpu_selector()          : No device of requested type available. -1 (PI_ERRO...
gpu_selector()          : No device of requested type available. -1 (PI_ERRO...
custom_selector(gpu)    : No device of requested type available. -1 (PI_ERRO...
custom_selector(cpu)    : No device of requested type available. -1 (PI_ERRO...
custom_selector(acc)    : No device of requested type available. -1 (PI_ERRO...