Fix accidentally forced std/allocator on no_std

[jaybosamiya-ms]

The cfg config for std/ALLOCATOR might be accidentally too permissive.

Specifically, as it currently stands:

#[cfg(any(test, not(feature = "std")))]
#[macro_use]
extern crate std;

This code brings in std even if the feature std is not enabled (because any would hold true if even one of the two conditions is true). Similarly, for ALLOCATOR.

By changing it to all instead of any, it is only applicable for tests for non-std configuration, which is what I believe the intention is here.

[tmfink]

thanks for the PR!