[ruby] Re-implemented "Ignore "Throwaway" AST Structures (#4982)"

[DavidBakerEffendi]

This correctly prevents re-use of nodes that are already being used elsewhere by ensuring deep copies.

[maltek]

@DavidBakerEffendi with this PR, some lambda references seem to get mixed up:

for this file https://github.com/OWASP/railsgoat/blob/c1e8ff1e3b24a1c48fcfc9fbee0f65dc296b49d9/config/routes.rb

When I query for the lambda referenced in the :dashboard section, I get the lambda from the :pay section instead:

ocular> cpg.call.codeExact("""resources :dashboard do
     |     collection do
     |       get "home"
     |       get "change_graph"
     |     end
     |   end""").argument(2).isTypeRef.typ.referencedTypeDecl.code.l
val res62: List[String] = List(
  """do
      collection do
        post "update_dd_info"
        post "decrypted_bank_acct_num"
      end
    end"""
)

[DavidBakerEffendi]

@maltek alright will have to revisit how I match "live" lambdas to references without regenerating said lambdas and duplicating them

[DavidBakerEffendi]

@maltek Found the issue, RubyExpression nodes don't inherently consider the span in the calculation of its hash, so when put into any hashed context, nodes that only rely on span collide. A fix to come

[DavidBakerEffendi]

Fix: #4986