Some `python/triton_kernels/tests/test_matmul.py::test_op` test cases don't work

[anmyachev]

Found in #5051

Need to fix/enable them.

[wdziurdz]

The failed tests are reproducible, and the work is still in progress.

[wdziurdz]

Still WIP no rout cause of issue. It looks two types of issue:

1. Scale computation mismatch (ref_y_scale vs tri_y_scale), mismatch between torch and Triton implementations

• only for dtypes float8_e4m3fn × float8_e4m3fn and with dimensions 1000-400-400
• Error: 0.0002-0.0005 difference exceeding 1e-10 tolerance
• failed 8 tests with signature test_matmul.py::test_op[*-1000-400-400-ragged-float8_e4m3fn-float8_e4m3fn-*]

2. Matrix multiplication with mxfloat8_e4m3fn × mxfloat4_e2m1 and split_k=9 produces incorrect results, mismatch between torch and Triton implementations.

• only for dtypes mxfloat8_e4m3fn × mxfloat4_e2m1 and with split_k > 1
• reference is 0 vs triton 120.0
• failed 32 tests with signature test_matmul.py::test_op[*-1000-704-800-ragged-mxfloat8_e4m3fn-mxfloat4_e2m1-8-2-1-9-*]

[wdziurdz]

In progress:
After this commit b39933c#diff-a60c3db3be9a7228578b96a8ee50091e997978e4390e682d2606cf3e2646bb0f, the number of failing tests increased to ~560.
The second issue from the previous update has been fixed; the first is still in progress. Also, about half of the failures were introduced by this commit and may be fixed in this PR
PR with fixes: #5128