Replace runTestCase with assert helpers [test/language/arguments-object]

test/language/arguments-object/10.5-7-b-2-s.js

test/language/arguments-object/10.5-7-b-3-s.js

test/language/arguments-object/10.5-7-b-4-s.js

test/language/arguments-object/10.6-10-c-ii-1-s.js

test/language/arguments-object/10.6-10-c-ii-1.js

test/language/arguments-object/10.6-10-c-ii-2-s.js

test/language/arguments-object/10.6-10-c-ii-2.js

test/language/arguments-object/10.6-13-a-2.js

test/language/arguments-object/10.6-13-a-3.js

test/language/arguments-object/10.6-14-1-s.js

test/language/arguments-object/10.6-14-b-1-s.js

test/language/arguments-object/10.6-14-c-1-s.js