Under normal circumstances, `rake -m test` will parallelize not only the build task, but also the test task.
With this patch, `rake -m test:run:serial` will parallelize the build tasks, but the test tasks will be done one by one in sequence.
The name of the task to be added is as follows:
| tasks to be added     | corresponding exist tasks
| --------------------- | ----------------
| `test:run:serial`     | `test:run`
| `test:run:serial:bin` | `test:run:bin`
| `test:run:serial:lib` | `test:run:lib`