Disable bootstrap rustc version check

Mitigates rust-lang#115065

Author: djkoloski

src/bootstrap/config.rs

@@ -1276,7 +1276,8 @@ impl Config {
  }
 
  config.initial_rustc = if let Some(rustc) = build.rustc {
- config.check_build_rustc_version(&rustc);
+ // FIXME(#115065): re-enable this check
+ // config.check_build_rustc_version(&rustc);
  PathBuf::from(rustc)
  } else {
  config.download_beta_toolchain();