simplify iterating through arglist

test/completions.bats

@@ -33,10 +33,7 @@ fi"
 # provide rbenv completions
 if [[ \$1 = --complete ]]; then
   shift 1
-  while [[ \$# -gt 0 ]]; do
-    echo \$1
-    shift 1
-  done
+  for arg; do echo \$arg; done
 else
   exit 1
 fi"

test/exec.bats

@@ -42,10 +42,9 @@ create_executable() {
   export RBENV_VERSION="2.0"
   create_executable "ruby" "#!$BASH
     echo \$0
-    while [[ \$# -gt 0 ]]; do
+    for arg; do
       # hack to avoid bash builtin echo which can't output '-e'
-      printf \"%s\\n\" \"\$1\"
-      shift 1
+      printf \"%s\\n\" \"\$arg\"
     done"
 
   run rbenv-exec ruby -w -e "puts 'hello world'" -- extra args