Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
RUN: not llvm-remark-size-diff %p/Inputs/unexpected-key.yaml %p/Inputs/1-func-1-instr-1-stack.yaml --parser=yaml 2>&1 | FileCheck %s ; CHECK: Expected 'NumInstructions', got 'Wrong'