Remove warning for volatile_store

[adpaco-aws]

Description of changes:

Removes the concurrency warning emitted on the codegen_volatile_store function, which is the only volatile operation remaining after the intrinsics audit.

Resolved issues:

Resolves #789

Call-outs:

Testing:

• How is this change tested? Existing regression.

• Is this a refactor change? No.

Checklist

• Each commit message has a non-empty body, explaining why the change was made
• Methods or procedures are documented
• Regression or unit tests are included, or existing tests cover the modified code
• My PR is restricted to a single feature or bugfix

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.