GH-50777: [CI][Dev] Fix shellcheck errors in the ci/scripts/r_test.sh

[hiroyuki-sato]

Rationale for this change

This is the sub issue #44748.

• SC1091: Not following: (error message here)
• SC2086: Double quote to prevent globbing and word splitting.
• SC2223: This default assignment may cause DoS due to globbing. Quote it.

shellcheck ci/scripts/r_test.sh

In ci/scripts/r_test.sh line 21:
: ${R_BIN:=R}
  ^---------^ SC2223 (info): This default assignment may cause DoS due to globbing. Quote it.


In ci/scripts/r_test.sh line 25:
pushd ${source_dir}
      ^-----------^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
pushd "${source_dir}"


In ci/scripts/r_test.sh line 30:
  . "${ARROW_PYTHON_VENV}/bin/activate"
    ^-- SC1091 (info): Not following: ./bin/activate: openBinaryFile: does not exist (No such file or directory)

For more information:
  https://www.shellcheck.net/wiki/SC1091 -- Not following: ./bin/activate: op...
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2223 -- This default assignment may cause...

What changes are included in this PR?

• SC1091: Add a ShellCheck directive to disable source file checking.
• SC2086: Quote variables.
• SC2223: Quote variables.

Are these changes tested?

Yes.

Are there any user-facing changes?

No.

• GitHub Issue: [CI][Dev] Fix shellcheck errors in the ci/scripts/r_test.sh #50777

[github-actions]

⚠️ GitHub issue #50777 has been automatically assigned in GitHub to PR creator.

[hiroyuki-sato]

@github-actions crossbow submit -g r

[github-actions]

Revision: 90394dd

Submitted crossbow builds: ursacomputing/crossbow @ actions-8500c66225

Task	Status
r-binary-packages
r-recheck-most
test-r-alpine-linux-cran
test-r-arrow-backwards-compatibility
test-r-depsource-system
test-r-dev-duckdb
test-r-devdocs
test-r-extra-packages
test-r-fedora-clang
test-r-gcc-11
test-r-gcc-12
test-r-install-local
test-r-install-local-minsizerel
test-r-linux-as-cran
test-r-linux-rchk
test-r-linux-sanitizers
test-r-linux-valgrind
test-r-m1-san
test-r-macos-as-cran
test-r-offline-maximal
test-r-ubuntu-22.04
test-r-versions
test-r-wasm

[kou]

+1

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 4 benchmarking runs that have been run so far on merge-commit 62d1311.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details.