[C++] Remove make_unique reimplementation

[asfimport]

The make_unique reimplementation in arrow/util/make_unique.h can simply be replace with std::make_unique.

Reporter: Antoine Pitrou / @pitrou
Assignee: Gang Wu / @wgtmac

Related issues:

• [C++] Remove pre-C++17 compatibility measures (is a child of)

PRs and other links:

• GitHub Pull Request #14204
• GitHub Pull Request #14218

_{Note: This issue was originally created as ARROW-17814. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
@wgtmac Do you want to submit a PR?

[asfimport]

Gang Wu / @wgtmac:
@pitrou Sure, I will work on it.

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 14204
#14204