…mment, then EOF

If a source file contains 1) a directive, followed by 2) a comment, and nothing else, then `@babel/parser` attaches the comment to the `Directive` node as a trailing comment.

The ESTree plugin handles `Directive` nodes by creating an `ExpressionStatement` node, then transferring information from the `Directive` node to the `ExpressionStatement` node. Previously, at the time it transfers information, comments hadn't yet been attached to the `Directive` node. And even if they had been, the ESTree plugin didn't do anything with comments attached to the `Directive` node. As a result, the source file's comment wasn't attached to any node in the resulting AST.

With this change, the ESTree plugin generates an AST in which the comment is attached to the `ExpressionStatement` node as a trailing comment.

…tatement