remove unnecessary variable assignments

[lm-noshiro]

What this patch does to fix the issue.

• removed unnecessary variable assignments

Link to any relevant issues or pull requests.

#1058

[bo-code-review-bot[bot]]

This PR needs Approvals as follows.

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[tsawada]

To reduce the amount of work on readability reviewers, please send readability review request after you get LGTM and Ownership Approval.

[lm-noshiro]

To reduce the amount of work on readability reviewers, please send readability review request after you get LGTM and Ownership Approval.

OK, I understand.

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[iizukak]

@lm-noshiro Can you check review comment?