GH-50855: [R] Fix shellcheck errors in the r/inst/build_arrow_static.sh - #50856

GH-50855: [R] Fix shellcheck errors in the r/inst/build_arrow_static.sh#50856

hiroyuki-sato wants to merge 4 commits into

apache:mainapache/arrow:mainfrom

hiroyuki-sato:topic/shellcheck-build_arrow_statichiroyuki-sato/arrow:topic/shellcheck-build_arrow_staticCopy head branch name to clipboard