*.js files out of the root directory cannot be compiled

gulpfile.js and other files are put in “tools” directory. Now I compile *.js under “builds” directory that is the same level as “tools” directory, but the compilation does not work.

// tools/gulpfile.js
```js
// doesn't work
gulp.task('test', function () {
gulp.src("../builds/*.js")
.pipe(babel())
.pipe(gulp.dest('../builds'));
})

// work
gulp.task('test', function () {
gulp.src("./*.js")
.pipe(babel())
.pipe(gulp.dest('./'));
})
```

Start with tools/gulpfile.js and reproduce the failing gulp.src("../builds/*.js") case against the sibling builds directory, then compare it with the working root-level glob. Trace how the plugin handles the source and destination paths and verify the fix by confirming that builds/*.js is compiled successfully.

Written by the indexing model from the issue text.