Actually build the compiler in bootstrap benchmark

This was broken after a recent bootstrap change.

Author: Kobzol

collector/src/compile/execute/rustc.rs

@@ -117,7 +117,7 @@ async fn record(
             .env("BOOTSTRAP_SKIP_TARGET_SANITY", "1")
             .arg("build")
             .arg("--stage")
-            .arg("0")
+            .arg("1")
             // We want bootstrap and the Cargos it spawns to have no parallelism --
             // if multiple rustcs are competing for jobserver tokens, we introduce
             // quite a bit of variance.