PR #124: Add RemoveCase and RemoveAction mutation operators

Agent Instructions

Click a suite to see its builds. Example suite for 16456eb1 :

https://staging.nix-ci.com/gh:NorfairKing:sydtest/refs%2Fpull%2F124%2Fmerge/16456eb1ed47322cd668f5dca9f629760d5a24ac

For more instructions, fetch https://staging.nix-ci.com/instructions .