Use precompiled dependencies in pub.

sdk/lib/_internal/pub_generated/lib/src/validator/executable.dart

 library pub.validator.executable;
 import 'dart:async';
 import 'package:path/path.dart' as p;
 import '../entrypoint.dart';
 import '../validator.dart';
 class ExecutableValidator extends Validator {
   ExecutableValidator(Entrypoint entrypoint) : super(entrypoint);
   Future validate() {
     final completer0 = new Completer();
     scheduleMicrotask(() {
       try {
         var binFiles = entrypoint.root.listFiles(
             beneath: "bin",
-            recursive: false).map(
-                ((path) => p.relative(path, from: entrypoint.root.dir))).toList();
+            recursive: false).map(((path) => entrypoint.root.relative(path))).toList();
         entrypoint.root.pubspec.executables.forEach(((executable, script) {
           var scriptPath = p.join("bin", "$script.dart");
           if (binFiles.contains(scriptPath)) return;
           warnings.add(
               'Your pubspec.yaml lists an executable "$executable" that '
                   'points to a script "$scriptPath" that does not exist.');
         }));
         completer0.complete(null);
       } catch (e0) {
         completer0.completeError(e0);
       }
     });
     return completer0.future;
   }
 }