spec(Lexer) add spec for good and bad unicode in the same string
spec(Lexer) add spec for good and bad unicode in the same string

rmosolgo/graphql-ruby,xuorig/graphql-ruby,nevesenin/graphql-ruby,xuorig/graphql-ruby,xuorig/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby