tests: relax expectations after llvm change 902ddda120a5

LLVM 22 is able to drop assumes that seem to not help further
optimizations, which actually seems to dramatically _help_ further
optimizations in some of our small test cases.

Author: durin42

tests/codegen-llvm/vec_pop_push_noop.rs

@@ -7,7 +7,6 @@
 pub fn noop(v: &mut Vec<u8>) {
     // CHECK-NOT: grow_one
     // CHECK-NOT: call
-    // CHECK: tail call void @llvm.assume
     // CHECK-NOT: grow_one
     // CHECK-NOT: call
     // CHECK: {{ret|[}]}}

tests/codegen-llvm/vecdeque_pop_push.rs

@@ -8,7 +8,6 @@ use std::collections::VecDeque;
 // CHECK-LABEL: @noop_back(
 pub fn noop_back(v: &mut VecDeque<u8>) {
     // CHECK-NOT: grow
-    // CHECK: tail call void @llvm.assume
     // CHECK-NOT: grow
     // CHECK: ret
     if let Some(x) = v.pop_back() {