fast query gen skips negacyclic

[chenyue42]

In client query generation code, the function rlwe_to_lwe computes a negacyclic_matrix. Later, in run_simple_ypir_rgsw_on_params, the query_row_last_row vector only uses the b part of the LWE ciphertexts. The negacyclic matrices seem to be useless in this case. I am not sure about the use of the how_many variable in function generate_query_over_prime. Please make sure it is safe to ignore using this variable.

This similar fix appears in YPIR's implementation as well.

Here is a quick test that should work well:
cargo run --release --bin inspire -- -v --num-items 32768 --item-size-bits 32768 --dim0 32768

The online client time reduces from ~1000ms to ~30ms

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