Build error due to atomic API change

[Victor-Nicolae Savu]

hvm fails to install because of a compilation error that is due to a change in the nightly API of the atomic crate. as_ptr was renamed to as_mut_ptr.

Reproduction:

cargo +nightly install hvm

Output:

[...]
error[E0599]: no method named `as_ptr` found for struct `AtomicU64` in the current scope
   --> /Users/[edited].cargo/registry/src/github.com-1ecc6299db9ec823/hvm-1.0.6/src/runtime/base/program.rs:161:32
    |
161 |             val += (*lvar.dups.as_ptr() & 0xFFF_FFFF) * EXT;
    |                                ^^^^^^ help: there is a method with a similar name: `as_mut_ptr`

[Victor-Nicolae Savu]

In fact, I was running an outdated version of nightly. Closing the issue :)