This patch [1] added the method `Attr#attribTopLevel` to validate the annotations of the package. Then the annotation validation was moved to the annotation pipeline [2] and the TopLevel tree node was refactored (added JCPackageDecl) [3]. So now the `Attr#attribTopLevel` is replaced by method `attribPackage` and actually is not used by any code. It is good to remove it.

[1]https://github.com/openjdk/jdk/commit/13d31713dc6ac7134d81abeb11a659df2104d71f
[2]https://github.com/openjdk/jdk/commit/da21af58f4811285f7050691d51fe32600c0e5f8
[3]https://github.com/openjdk/jdk/commit/9783b65028eba41796c3e05ebb545b1a722f56b0