In `extend/ENV/std.rb`, the methods `set_cpu_flags` and
`set_cpu_cflags` have been violating the `Naming/AccessorMethodName`
cop.

A recent modification in #7e13b374 woke up the cop. That means we’re
likely dealing with legacy code here, predating the introduction of
RuboCop into Homebrew.

This commit disables the cop for either method. I believe refactoring
wouldn’t currently be worth the effort, especially given that
`#set_cpu_cflags` is mostly called without arguments.