A lot of tools use Ripper/RubyVM::AbstractSyntaxTree to determine
if a source is valid. These tools both create an AST instead of
providing an API that will return a boolean only.
This new API only creates the C structs, but doesn't bother
reifying them into Ruby/the serialization API. Instead it only
returns true/false, which is significantly more efficient.
https://github.com/ruby/prism/commit/7014740118