remove obsolete comment

Author: tshepang

src/bootstrap/bin/rustc.rs

@@ -97,10 +97,6 @@ fn main() {
         // This... is a bit of a hack how we detect this. Ideally this
         // information should be encoded in the crate I guess? Would likely
         // require an RFC amendment to RFC 1513, however.
-        //
-        // `compiler_builtins` are unconditionally compiled with panic=abort to
-        // workaround undefined references to `rust_eh_unwind_resume` generated
-        // otherwise, see issue https://github.com/rust-lang/rust/issues/43095.
         if crate_name == Some("panic_abort")
             || crate_name == Some("compiler_builtins") && stage != "0"
         {