Remove unused code (restructure part 4)

[aslesarenko]

In this PR:

• unnecessary annotations are removed
• code cleanup

[codecov]

Codecov Report

Merging #868 (637a7f0) into v5.0.6-RC (0f4fa86) will increase coverage by 0.30%.
The diff coverage is 76.36%.

@@              Coverage Diff              @@
##           v5.0.6-RC     #868      +/-   ##
=============================================
+ Coverage      75.71%   76.01%   +0.30%     
=============================================
  Files            220      221       +1     
  Lines          14357    14333      -24     
  Branches         512      489      -23     
=============================================
+ Hits           10870    10895      +25     
+ Misses          3487     3438      -49     

Impacted Files	Coverage Δ
...on/src/main/scala/scalan/util/ReflectionUtil.scala	100.00% <ø> (+53.33%)	⬆️
core/src/main/scala/scalan/primitives/Thunks.scala	59.82% <ø> (ø)
...ary-api/src/main/scala/special/SpecialPredef.scala	0.00% <0.00%> (ø)
...-api/src/main/scala/special/collection/Colls.scala	84.61% <ø> (ø)
...src/main/scala/special/wrappers/WrappersSpec.scala	100.00% <ø> (ø)
...ain/scala/special/collection/CollsOverArrays.scala	79.62% <ø> (ø)
.../src/main/scala/special/collection/CollsUnit.scala	0.00% <0.00%> (ø)
...ry/src/main/scala/special/sigma/SigmaDslUnit.scala	0.00% <ø> (ø)
.../src/main/scala/org/ergoplatform/ErgoAddress.scala	96.29% <ø> (ø)
...tate/src/main/scala/org/ergoplatform/ErgoBox.scala	92.30% <ø> (ø)
... and 12 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.