remove dead code

Author: WaffleLapkin

src/tools/compiletest/src/common.rs

@@ -6,7 +6,6 @@ use std::sync::OnceLock;
 use build_helper::git::GitConfig;
 use camino::{Utf8Path, Utf8PathBuf};
 use semver::Version;
-use serde::de::{Deserialize, Deserializer, Error as _};
 
 use crate::executor::{ColorConfig, OutputFormat};
 use crate::fatal;
@@ -1172,11 +1171,6 @@ fn rustc_output(config: &Config, args: &[&str], envs: HashMap<String, String>) -
     String::from_utf8(output.stdout).unwrap()
 }
 
-fn serde_parse_u32<'de, D: Deserializer<'de>>(deserializer: D) -> Result<u32, D::Error> {
-    let string = String::deserialize(deserializer)?;
-    string.parse().map_err(D::Error::custom)
-}
-
 #[derive(Debug, Clone)]
 pub struct TestPaths {
     pub file: Utf8PathBuf,         // e.g., compile-test/foo/bar/baz.rs