Before:
  Save g:ale_awk_gawk_executable
  Save g:ale_awk_gawk_options
  unlet! g:ale_awk_gawk_executable
  unlet! g:ale_awk_gawk_options

  runtime ale_linters/awk/gawk.vim

After:
  Restore
  unlet! b:command_tail
  unlet! b:ale_awk_gawk_executable
  unlet! b:ale_awk_gawk_options

  call ale#linter#Reset()

Execute(The executable should be used in the command):
  AssertEqual
  \ 'gawk'
    \ . " --source 'BEGIN { exit } END { exit 1 }'"
    \ . '  ' . '-f %t --lint /dev/null',
  \ ale_linters#awk#gawk#GetCommand(bufnr(''))

  let b:ale_awk_gawk_executable = '/other/gawk'

  AssertEqual
  \ '/other/gawk'
    \ . " --source 'BEGIN { exit } END { exit 1 }'"
    \ . '  ' . '-f %t --lint /dev/null',
  \ ale_linters#awk#gawk#GetCommand(bufnr(''))

  let b:ale_awk_gawk_executable = 'gawk'
  let b:ale_awk_gawk_options = '--something'

  AssertEqual
  \ 'gawk'
    \ . " --source 'BEGIN { exit } END { exit 1 }'"
    \ . ' --something'
    \ . ' ' . '-f %t --lint /dev/null',
  \ ale_linters#awk#gawk#GetCommand(bufnr(''))