Remove rule requiring non-nil block-style statements to be semi-terminated

This is a subtle rule that no longer seems to be required.

src/libsyntax/parse/classify.rs

@@ -27,9 +27,6 @@ fn stmt_ends_with_semi(stmt: ast::stmt) -> bool {
       ast::stmt_expr(e, _) {
         ret expr_requires_semi_to_be_stmt(e);
       }
-      ast::stmt_semi(e, _) {
-        ret false;
-      }
     }
 }