Upgrade @glimmer/syntax to latest (#7245)
* Remove simple-html-tokenizer resolution
* Remove outdated filter
I'm not 100% sure but I guess it was useful with previous
@glimmer/syntax versions
* Remove unused code
* Upgrade @glimmer/syntax and simple-html-tokenizen
Co-authored-by: Georgii Dolzhykov <thorn.mailbox@gmail.com>