Set CFG_RELEASE for tools in bootstrap/tool.rs
Set CFG_RELEASE for tools in bootstrap/tool.rs

Since rustc-ap-* v659 we now need to set CFG_RELEASE for
rustc-ap-rustc_attr for `#[cfg(version(...))]` to work.

Co-authored-by: Eric Huss <86e9a1225f68685476c193e9a8bd0ebd08404a98@users.noreply.github.com>

graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust