message: Optimize parser
  Add some short-circuiting
diff: @@ -275,7 +275,7 @@ pub trait CharExt: Copy {
  None => return false,
  };
  // TODO: Use Unicode ID instead of XID.
  - c == '$' || c == '_' || UnicodeXID::is_xid_start(c)
  + c == '$' || c == '_' || c.is_ascii_alphabetic() || UnicodeXID::is_xid_start(c)
  }
  /// Test whether a given character is part of an identifier.
  @@ -285,7 +285,11 @@ pub trait CharExt: Copy {
  None => return false,
  };
  // TODO: Use Unicode ID instead of XID.
  - c == '$' || c == '\u{200c}' || c == '\u{200d}' || UnicodeXID::is_xid_continue(c)
  + c == '$'
  + || c == '\u{200c}'
  + || c == '\u{200d}'
  + || c.is_ascii_alphanumeric()
  + || UnicodeXID::is_xid_continue(c)
  }
  /// See https://tc39.github.io/ecma262/#sec-line-terminators
  