Add test coverage for polynomial evaluations

[ZER0]

The test vectors are calculate by @marta-belles, assuming the ifft
function is actually correct.

Resolves: #586

[codecov]

Codecov Report

Merging #621 (30dd939) into add_lookups (38220d0) will increase coverage by 38.57%.
The diff coverage is 99.12%.

❗ Current head 30dd939 differs from pull request most recent head 8fe54e1. Consider uploading reports for the commit 8fe54e1 to get more accurate results

@@               Coverage Diff                @@
##           add_lookups     #621       +/-   ##
================================================
+ Coverage        59.11%   97.68%   +38.57%     
================================================
  Files               52       54        +2     
  Lines             7183     4111     -3072     
  Branches          2432        0     -2432     
================================================
- Hits              4246     4016      -230     
+ Misses             755       95      -660     
+ Partials          2182        0     -2182     

Impacted Files	Coverage Δ
src/commitment_scheme/kzg10/key.rs	98.53% <ø> (+45.57%)	⬆️
src/commitment_scheme/kzg10/proof.rs	100.00% <ø> (+39.53%)	⬆️
src/constraint_system/witness.rs	100.00% <ø> (+8.33%)	⬆️
src/lib.rs	100.00% <ø> (+4.25%)	⬆️
src/plonkup/multiset.rs	98.70% <ø> (+58.03%)	⬆️
src/plonkup/table/lookup_table.rs	97.87% <ø> (+58.98%)	⬆️
src/plonkup/table/preprocess.rs	95.65% <ø> (+72.70%)	⬆️
src/plonkup/table/witness_table.rs	100.00% <ø> (+57.57%)	⬆️
src/proof_system/linearisation_poly.rs	98.90% <ø> (+28.44%)	⬆️
src/proof_system/verifier.rs	85.00% <ø> (+29.73%)	⬆️
... and 84 more

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[vlopes11]

LGTM