Merge pull request #352 from bocoup/es6-regexp-u

...lt-ins/RegExp/prototype/Symbol.match/get-unicode-error.js

...ns/RegExp/prototype/Symbol.match/u-advance-after-empty.js

...-ins/RegExp/prototype/Symbol.replace/get-unicode-error.js

.../RegExp/prototype/Symbol.replace/u-advance-after-empty.js

...ins/RegExp/prototype/Symbol.search/u-lastindex-advance.js

...xp/prototype/Symbol.split/u-lastindex-adv-thru-failure.js

...gExp/prototype/Symbol.split/u-lastindex-adv-thru-match.js

test/built-ins/RegExp/prototype/exec/u-captured-value.js

test/built-ins/RegExp/prototype/exec/u-lastindex-adv.js

test/built-ins/RegExp/prototype/exec/u-lastindex-value.js

test/built-ins/RegExp/prototype/flags/u-attr-err.js

test/built-ins/RegExp/prototype/flags/u-coercion.js

test/built-ins/RegExp/prototype/flags/u.js

test/built-ins/RegExp/prototype/unicode/length.js

test/built-ins/RegExp/prototype/unicode/name.js

test/built-ins/RegExp/prototype/unicode/prop-desc.js

test/built-ins/RegExp/prototype/unicode/this-invald-obj.js

test/built-ins/RegExp/prototype/unicode/this-non-obj.js

test/built-ins/RegExp/prototype/unicode/this-regexp.js

test/language/literals/regexp/u-astral.js