Remove various duplicated code in core-coder

• Related issues: #2347 (closed)
• Requested reviewers: @vaillancour or @tamarapu

Reason why this change is needed

• Remove various duplicated code in core-coder.

Description of the change

• Remove various duplicated code in core-coder.
• Removes 12 (generally short) functions corresponding to around 900 source-code lines.

Affected operating points

• All is BE.

Closes #2347 (closed)