[2Dblock] fix minicore test's runtime checks

[januszjah]

As can be seen in demo PR: #5326
There are at least these errors when enabling asserts on all CI test:

=================================== FAILURES ===================================
_______________ python/test/unit/language/test_block_pointer.py ________________
[gw2] linux -- Python 3.10.19 /opt/hostedtoolcache/Python/3.10.19/x64/bin/python
worker 'gw2' crashed while running 'python/test/unit/language/test_block_pointer.py::test_block_ptr_matmul_no_scf[shape0-4]'
_______________ python/test/unit/language/test_block_pointer.py ________________
[gw0] linux -- Python 3.10.19 /opt/hostedtoolcache/Python/3.10.19/x64/bin/python
worker 'gw0' crashed while running 'python/test/unit/language/test_block_pointer.py::test_block_ptr_matmul_no_scf[shape1-8]'

It says that worker crashed because it got SIGABRT (that's what __assert_fail on device does).

We need to check if asserts are legit or too restrictive. If they are valid then tests should be fixed, because now they work only because of 'guaranteed' fallback of returning zeros when reading out-of-bounds etc or it's UB.

Environment details

Triton: 3.4
GPU: MAX 1100