[R] Remove arrow-without-arrow wrapping

[asfimport]

Depends on ARROW-10734. If we can successfully build Arrow with the C++ library on all of CRAN's platforms, we can remove the conditional build wrapping and codegen. This will simplify the R package's C++ code, remove some bloat, and make for a simpler user experience.

We do still though need the conditional build of S3 support.

Reporter: Neal Richardson / @nealrichardson
Assignee: Neal Richardson / @nealrichardson

Related issues:

• [R] split code generation into mock and implementation (is related to)

PRs and other links:

• GitHub Pull Request #9209

_{Note: This issue was originally created as ARROW-10735. Please see the migration documentation for further details.}

[asfimport]

Neal Richardson / @nealrichardson:
See discussion on ARROW-10734. Since we're already on the CRAN Solaris blocklist for being flaky/incomplete build anyway, I think the arrow-without-arrow doesn't help us anymore--it's not saving us from CRAN hassle. We build successfully on every other CRAN platform. cc @romainfrancois @bkietz

[asfimport]

Neal Richardson / @nealrichardson:
Issue resolved by pull request 9209
#9209