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

task_scheduler/go/db/memory_test.go

 package db
 
 import "testing"
 
 func TestInMemoryDB(t *testing.T) {
         TestDB(t, NewInMemoryDB())
 }
 
 func TestInMemoryTooManyUsers(t *testing.T) {
         TestTooManyUsers(t, NewInMemoryDB())
 }
 
 func TestInMemoryConcurrentUpdate(t *testing.T) {
         TestConcurrentUpdate(t, NewInMemoryDB())
 }
 
 func TestInMemoryUpdateWithRetries(t *testing.T) {
         TestUpdateWithRetries(t, NewInMemoryDB())
 }