message: Reenable the size assertions
  Summary: Follow up to (https://github.com/facebookexperimental/starlark-rust/commit/df39dc80004e294053cdc1c72be05b88af78a3cc), ensure the size doesn't regress, without being precise about it.
diff: @@ -21,6 +21,7 @@ use std::fmt;
  use std::fmt::Debug;
  use std::fmt::Display;
  use std::fmt::Formatter;
  +use std::mem;
  use derivative::Derivative;
  use gazebo::prelude::*;
  @@ -86,9 +87,9 @@ pub(crate) type AstStmt = AstStmtP<AstNoPayload>;
  // but we equally don't want to regress without noticing.
  // These two data structures reduced in size with nightly ~10 Sep 2022.
  -// Once that date is in the distant past, we should reenable these assertions.
  -// assert_eq_size!(AstStmt, [usize; 12]);
  -// assert_eq_size!(AstExpr, [usize; 9]);
  +// Once that date is in the distant past, we should make these assertions equality.
  +const _: () = assert!(mem::size_of::<AstStmt>() <= mem::size_of::<[usize; 12]>());
  +const _: () = assert!(mem::size_of::<AstExpr>() <= mem::size_of::<[usize; 9]>());
  assert_eq_size!(AstAssign, [usize; 7]);
  /// A representation of a Starlark module abstract syntax tree.
  