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

task_scheduler/go/scheduling/specs.go

-package task_scheduler
+package scheduling
 
 import (
         "encoding/json"
         "fmt"
         "strings"
         "sync"
         "time"
 
         "go.skia.org/infra/go/gitinfo"
 )
@@ skipping 259 matching lines @@
 
         for _, v := range vertices {
                 if !v.visited {
                         if err := visit(v); err != nil {
                                 return err
                         }
                 }
         }
         return nil
 }