[task scheduler] Move files from build_scheduler/ to task_scheduler/

task_scheduler/go/db/cache_test.go

 package db
 
 import (
         "testing"
         "time"
 
         assert "github.com/stretchr/testify/require"
         "go.skia.org/infra/go/testutils"
 )
 
@@ skipping 188 matching lines @@
 
         // Update the task.
         t3.Commits = []string{"c", "d", "f"}
         assert.False(t, t3.Done())
         assert.NoError(t, db.PutTask(t3))
         assert.NoError(t, c.Update())
         tasks, err = c.UnfinishedTasks()
         assert.NoError(t, err)
         testutils.AssertDeepEqual(t, []*Task{t3}, tasks)
 }