Enable test_block_copy with lower bound check

[ienkovich]

Describe the bug

Recently added tests for block pointer copy fail on CPU when lower bound check is required. This happens because CPU backend relies on vector transfer_read/writer for checks, but those operations check upper bound only.

To reproduce, remove skip from the test and run python -m pytest --device cpu python/test/unit/language/test_block_pointer.py::test_block_copy

Environment details