Missed a bit of the merge in the test runner.

Author: vext01

src/librustc_interface/tests.rs

@@ -8,7 +8,7 @@ use rustc_errors::{emitter::HumanReadableErrorType, registry, ColorConfig};
 use rustc_session::config::{build_configuration, build_session_options, to_crate_config};
 use rustc_session::config::{rustc_optgroups, ErrorOutputType, ExternLocation, Options, Passes};
 use rustc_session::config::{ExternEntry, LinkerPluginLto, LtoCli, SwitchWithOptPath};
-use rustc_session::config::{Externs, OutputType, OutputTypes, SymbolManglingVersion};
+use rustc_session::config::{Externs, OutputType, OutputTypes, SymbolManglingVersion, TracerMode};
 use rustc_session::lint::Level;
 use rustc_session::search_paths::SearchPath;
 use rustc_session::{build_session, Session};