Basop 2402 simplification of arithmetic codec subfunctions

• Related issues: #2402
• Requested reviewers: @multrus

Reason why this change is needed

• This MR should improve the complexity of the arithmetic codec. It uses simplified integer MSU operation (32x16) instead of multiple operations. All modifications must remain bit-exact to the legacy code.
• Also harmonizes the arithmetic encoder functions between EVS and IVAS for the TCX/IGF arithemtic coder

Description of the change

• See above

Affected operating points

• All changes are BE.