(Computed Property Names) Re-organize, add assertion messages.

test/language/computed-property-names/basics/number.js

test/language/computed-property-names/basics/string.js

test/language/computed-property-names/basics/symbol.js

...mputed-property-names/class/accessor/getter-duplicates.js

...language/computed-property-names/class/accessor/getter.js

...mputed-property-names/class/accessor/setter-duplicates.js

...language/computed-property-names/class/accessor/setter.js

...rty-names/class/method/constructor-cannot-be-generator.js

...operty-names/class/method/constructor-cannot-be-getter.js

...operty-names/class/method/constructor-cannot-be-setter.js

...property-names/class/method/constructor-no-duplicate-1.js

...property-names/class/method/constructor-no-duplicate-2.js

...property-names/class/method/constructor-no-duplicate-3.js

...guage/computed-property-names/class/method/constructor.js

...anguage/computed-property-names/class/method/generator.js

test/language/computed-property-names/class/method/number.js

test/language/computed-property-names/class/method/string.js

test/language/computed-property-names/class/method/symbol.js

...uted-property-names/class/static/generator-constructor.js

...age/computed-property-names/class/static/method-number.js