`report_internal_error` does not respect `stdout` and `stderr` in several places

When using mypy as a library and passing stdout and stderr into build.build it is reasonable to expect that it will be respected for all cases.

But, there are several places where report_internal_error does not respect the passed value and just dumps everything into sys.stdout:

• checker.py
• checkexpr.py
• semanal.py

But, there also places where report_internal_error is called with the correct streams:

• build.py

I suggest to add stdout and stderr props to Options class. It would be possible to easily work with them from all these three missed places.

まず、build.build から Options クラスを経由する stdout と stderr の流れを追い、次に checker.py、checkexpr.py、semanal.py、build.py にある report_internal_error の呼び出しを調べます。3 つの見落とされていた呼び出し箇所が sys.stdout ではなく渡されたストリームを使用し、build.py の既存の動作を維持できれば完了です。