[FIX][TIR] Conservatively analyze unsigned branch conditions

[sepcnt]

Fixes #20343.
Fixes tile-ai/tilelang#3235.

Unsigned branch conditions can crash block access-region analysis because the inequality solver constructs negative coefficients using unsigned variable types, raising cannot make uint from negative value -1.
Keep unsupported unsigned conditions unresolved and conservatively analyze both branches, while preserving independent signed bounds.
Add regression coverage for zero comparisons, high-bit thresholds, wraparound predicates, and mixed signed/unsigned conditions.

[tqchen]

Is this case from a real use-case, or AI/fuzzer, if so would be good to know the background.

The regression tests is too broad

[sepcnt]

Is this case from a real use-case, or AI/fuzzer, if so would be good to know the background.

The regression tests is too broad

This came from a compilation error in a differentiable renderer kernel for winding number calculation.

[tqchen]

Would be good to understand further on the shape of differentiable renderer kernel

please try to narrow the coverage, seems the error comes in arith, so it should be in a form of arith only testcase, and not through read write region

[tqchen]

test should be in python

[tqchen]

cc @tlopex would be good to see if we can have a more narrow check other than disabling, good to see candidates here and learnings