fails:Exception#set_backtrace accepts an Array of Strings
fails:Exception#set_backtrace allows the user to set the backtrace from a rescued exception
fails:Exception#set_backtrace accepts an empty Array
fails:Exception#set_backtrace accepts a String
fails:Exception#set_backtrace accepts nil
fails:Exception#set_backtrace raises a TypeError when passed a Symbol
fails:Exception#set_backtrace raises a TypeError when the Array contains a Symbol
fails:Exception#set_backtrace raises a TypeError when the array contains nil
fails:Exception#set_backtrace raises a TypeError when the argument is a nested array
