[WIP] Revert "GH-41407: [C++] Use static method to fill scalar scratch spac…

[jonkeane]

…e to prevent ub (#41421)"

This reverts commit 0ef7351.

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on GitHub? https://github.com/apache/arrow/issues/new/choose

Opening GitHub issues ahead of time contributes to the Openness of the Apache Arrow project.

Then could you also rename the pull request title in the following format?

GH-${GITHUB_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

In the case of PARQUET issues on JIRA the title also supports:

PARQUET-${JIRA_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - Contributing Overview

[jonkeane]

@github-actions crossbow submit test-r-linux-valgrind

[github-actions]

Revision: 109db2d9c35399a0c111414da4f14e8d5e04825b

Submitted crossbow builds: ursacomputing/crossbow @ actions-57c6070d0e

Task	Status
test-r-linux-valgrind