Add missing static semantics methods for modules
Use loading tasks for initialisation script execution for better error reporting
Minor clean-up: remove local variables
Remove redundant type checks
Move Date/Number/Math/String/RegExp to sub-packages based on spec structure
Shared runtime executor may have been shutdown already, create a temporary executor service in that case
Make sure ErrorObject#toString() does not run any script code
Add class name to class methods for better stacktraces
Enable previously disabled tests now that other engines provide more ES6 support or ES6 spec issues have been resolved
Use ICU for string normalization since they support a more recent Unicode version