Pure implementation should reject JSON with missing closing tokens ("{" and "[")

[backus]

The C extension JSON parser behaves as expected:

require 'json'

JSON::VERSION   # => "2.0.3"
JSON.parse('[') # !> 409: unexpected token at '' (JSON::ParserError)
JSON.parse('{') # !> 743: unexpected token at '{' (JSON::ParserError)

The pure implementation does not:

require 'json/pure'

JSON::VERSION   # => "2.0.3"
JSON.parse('{') # => {}
JSON.parse('[') # => []

[marcandre]

Confirmed in master