Use toArray instead of toTypedArray in ArrayDeque

[MukjepScarlet]

toArray is much faster than toTypedArray on JVM. And we don't need a typed array here.

[fzhinkin]

There's no public Collection.toArray function, so the stdlib won't compile after applying the suggested change.

Please make sure that code compiles and tests pass (you can execute the coreLibsTest Gradle task for that) before opening a PR.

Performance-related changes, in general, have to be accompanied by benchmarks showing performance difference before and after changes. For changes affecting multiple targets, performance needs to be evaluated for all these targets.

[MukjepScarlet]

@fzhinkin Hi! I have a problem on this. Because the ArrayDeque is declared in common module, so I can't implement JVM-only functions (like toArray here) in it. Is it possible to make platform-specific implementation for classes declared in common module, while it might not exist on other platforms?

[fzhinkin]

@MukjepScarlet, in theory, you can introduce an expect function and actualize it differently depending on a platform. But before doing that, it worth ensuring that all these efforts would actually result in a better performance (by writing and running benchmarks).