Change gas consumption amount when call set return data.

[Benzbeeb]

Implementation details

1. Change gas consume = spansize
2. Check env.RetData == nil before set return data
3. Implement test

Please ensure the following requirements are met before submitting a pull request:

• The pull request is targeted against the correct target branch
• The pull request is linked to an issue with appropriate discussion and an accepted design OR is linked to a spec that describes the work.
• The pull request includes a description of the implementation/work done in detail.
• The pull request includes any and all appropriate unit/integration tests
• You have added a relevant changelog entry to CHANGELOG_UNRELEASED.md
• You have re-reviewed the files affected by the pull request (e.g. using the Files changed tab in the Github PR explorer)

If this PR doesn't need to be merged into v1.0.6 please remove this option:

• The pull request has been cherry-picked to rc/1.0.6

[render]

Your Render PR Server URL is https://d3n-scan-pr-2292.onrender.com.

Follow its progress at https://dashboard.render.com/static/srv-bsbvi5g951ce3s6rm8vg.

[sorawit]

Looks great!