Remove unused variables

test/built-ins/Array/prototype/every/15.4.4.16-2-15.js

test/built-ins/Array/prototype/every/15.4.4.16-7-c-i-23.js

test/built-ins/Array/prototype/filter/15.4.4.20-2-15.js

test/built-ins/Array/prototype/filter/15.4.4.20-9-c-i-23.js

test/built-ins/Array/prototype/forEach/15.4.4.18-2-15.js

test/built-ins/Array/prototype/forEach/15.4.4.18-7-c-i-23.js

test/built-ins/Array/prototype/indexOf/15.4.4.14-1-17.js

test/built-ins/Array/prototype/indexOf/15.4.4.14-2-15.js

test/built-ins/Array/prototype/indexOf/15.4.4.14-9-b-i-23.js

test/built-ins/Array/prototype/lastIndexOf/15.4.4.15-1-17.js

test/built-ins/Array/prototype/lastIndexOf/15.4.4.15-2-15.js

...ilt-ins/Array/prototype/lastIndexOf/15.4.4.15-8-b-i-23.js

test/built-ins/Array/prototype/map/15.4.4.19-2-15.js

test/built-ins/Array/prototype/map/15.4.4.19-8-c-i-23.js

test/built-ins/Array/prototype/reduce/15.4.4.21-2-15.js

...uilt-ins/Array/prototype/reduce/15.4.4.21-8-b-iii-1-23.js

test/built-ins/Array/prototype/reduce/15.4.4.21-9-c-i-23.js

test/built-ins/Array/prototype/reduceRight/15.4.4.22-2-15.js

...ins/Array/prototype/reduceRight/15.4.4.22-8-b-iii-1-23.js

...ilt-ins/Array/prototype/reduceRight/15.4.4.22-9-c-i-23.js