Refactor tests for static methods creation and fetching

[leobalter]

Ref #2504
Ref tc39/ecma262#1490

@scole66 The tests are now correct with the current specs since tc39/ecma262#1490 has been merged.

There wasn't much to change I added some info content to help clarifying how the properties are set during the class evaluation and fetched from Object.getOwnPropertyNames and Object.getOwnPropertySymbols.

I also removed the assert messages as compareArray does a good job showing the actual and expected values if anything fails.

For the current tests failures, let's ping @codehag @anba @syg.

[anba]

SpiderMonkey test failures for these files are tracked at https://bugzilla.mozilla.org/show_bug.cgi?id=1629803.

[leobalter]

Thank you, @anba, I value this information because sometime it's a bit hard to map failing tests to existing filed bugs, if any.

[rwaldron]

@syg heads for failures in V8