Change Box to Arc for CompiledClass

[fguthmann]

Change Box to Arc for CompiledClass #926

Description

Change Box to Arc for CompiledClass since they get copied most of the time between the caches and their users, and are essentially read-only.

Checklist

• Linked to Github Issue
• Unit tests added
• Integration tests added.
• This change requires new documentation.
• Documentation has been added/updated.

[codecov-commenter]

Codecov Report

Merging #926 (4c3e5d5) into main (673985f) will not change coverage.
The diff coverage is 64.00%.

@@           Coverage Diff           @@
##             main     #926   +/-   ##
=======================================
  Coverage   90.82%   90.82%           
=======================================
  Files          54       54           
  Lines       13597    13597           
=======================================
  Hits        12350    12350           
  Misses       1247     1247           

Files Changed	Coverage Δ
...rc/services/api/contract_classes/compiled_class.rs	4.34% <25.00%> (ø)
src/state/in_memory_state_reader.rs	90.76% <33.33%> (ø)
src/state/cached_state.rs	90.43% <57.14%> (ø)
src/transaction/deploy.rs	90.43% <75.00%> (ø)
src/execution/execution_entry_point.rs	97.27% <100.00%> (ø)
src/state/state_cache.rs	96.33% <100.00%> (ø)
src/transaction/declare_v2.rs	83.72% <100.00%> (ø)