Remove some useless #[allow()]s in tests

tests/ui/issues/issue-3029.rs

@@ -2,9 +2,7 @@
 // error-pattern:so long
 // ignore-emscripten no processes
 
-#![allow(unused_allocation)]
 #![allow(unreachable_code)]
-#![allow(unused_variables)]
 
 fn main() {
     let mut x = Vec::new();

tests/ui/macros/rfc-2011-nicer-assert-messages/all-expr-kinds.rs

@@ -4,7 +4,7 @@
 // run-pass
 // needs-unwind Asserting on contents of error message
 
-#![allow(path_statements, unused_allocation)]
+#![allow(path_statements)]
 #![feature(box_syntax, core_intrinsics, generic_assert, generic_assert_internals)]
 
 macro_rules! test {