Compiling code with stray closing tag throws

[Conduitry]

Compiling code with a stray closing tag throws an error here as parent is undefined. This used to be more elegantly handled in 1.8.0.

REPL - 1.8.0 - 1.8.1

(I actually noticed this because in a project I had been using some (apparently!) bad markup, and had a <pre> element inside of a <p>. With 1.8.1, this now automatically closes the <p> when it reaches the <pre>, and then Svelte gets confused when it later hits the </p>.)

[Conduitry]

Well maybe not that elegantly handled in 1.8.0 - REPL - if there's more text after the closing tag, there is still an exception thrown.

[Rich-Harris]

Good catch, thanks — opened #323