Fix dump of tracing legend (#43263)

src/executeCommandLine/executeCommandLine.ts

@@ -501,7 +501,7 @@ namespace ts {
         updateSolutionBuilderHost(sys, cb, buildHost);
         const builder = createSolutionBuilder(buildHost, projects, buildOptions);
         const exitStatus = buildOptions.clean ? builder.clean() : builder.build();
-        tracing?.dumpLegend();
+        dumpTracingLegend(); // Will no-op if there hasn't been any tracing
         return sys.exit(exitStatus);
     }