Fix typo: acos -> acosh
Duplicate property name and method definitions are always a SyntaxError
Don't allow instances for helper class
Remove unnecessary casts
Add support for callable input arguments
Use [[Call]] instead of [[Construct]] to create new native error instances to avoid hitting a user-defined @@create hook
Use [[Call]] instead of [[Construct]] to avoid calling a user-defined @@create hook for the Error type
Update exclusion list for webkit tests
Use [[Call]] instead of [[Construct]] to avoid calling a user-defined @@create hook on RegExp