Deque and the OrderedSet/OrderedDictionary types are using floating-point arithmetic to resize themselves, for no particularly good reason. Rewrite them to use integer arithmetic instead.

This is a record-breakingly slow reaction to @rauhul's 2024 observation that FPUs aren't necessarily available in all environments that may want to use these types.

Checklist

• I've read the Contribution Guidelines
• My contributions are licensed under the Swift license.
• I've followed the coding style of the rest of the project.
• I've added tests covering all new code paths my change adds to the project (if appropriate).
• I've added benchmarks covering new functionality (if appropriate).
• I've verified that my change does not break any existing tests or introduce unexplained benchmark regressions.
• I've updated the documentation if necessary.