[TEST] Fix `test_core.py::test_dot` with `input_precision in ("bf16x3", "bf16x6")`

Tests are added in upstream commit https://github.com/intel/intel-xpu-backend-for-triton/commit/33e7dc2d799ae6442e8b6a7a73c64a8ecbca2124, and merged in #5362.

This issue is to determine if they can/should be handled on XPU.