Replace runTestCase with assert helpers [test/built-ins/Array/prototype/reduce]

test/built-ins/Array/prototype/reduce/15.4.4.21-0-1.js

test/built-ins/Array/prototype/reduce/15.4.4.21-0-2.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-11.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-12.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-14.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-15.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-4.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-6.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-7.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-8.js

test/built-ins/Array/prototype/reduce/15.4.4.21-1-9.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-1.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-2.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-3.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-4.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-5.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-6.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-7.js

test/built-ins/Array/prototype/reduce/15.4.4.21-10-8.js

test/built-ins/Array/prototype/reduce/15.4.4.21-2-1.js