pw_tokenizer: Update generate_hash_test_data.py to disable lints

Cleanup change 6d642e4a14fee7db4386a0da1480f8dfac2911eb modified
generated_hash_test_cases.h without updating the script that generated
that file.  Instead of updating the script to have conditional output
based on the string being zero length or not, we disable this lint
on this line.

Change-Id: Iaa0572f4c5d3600ef469d2d838e19da46af1e8d9
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/147711
Reviewed-by: Keir Mierle <keir@google.com>
Commit-Queue: Erik Gilling <konkers@google.com>