Fix persistent CAGRA regressions

[achirkin]

Fix peristent cagra kernel bugs:

1. Wrong arguments passed to the persistent kernel Convert non-type template parameters to runtime parameters in CAGRA search to cut binary size #1498 . Didn't catch this at compile time, because all affected parameters are of the same type. Never crashed in tests because of a lucky parameter combinations. But did crash in the example code.
2. Some changes in RMM over multiple versions made the pool allocator a bad choice for high-concurrency code, leading to the non-persistent async kernel call loop swap the CPU and hang forever.
3. Improved the speed of both implementations in the async loop by reducing the thread-launch overhead. Before: exactly work_size were spawned within a loop, competely dominating the runtime. After: n_threads are spawned and run an inner work loop over their shares of the input data. n_threads here is optimal for each implementation (persistent kernel requiring many more threads). The launch overheads are still significant, but do not overwhelm the useful work times.

[cjnolet]

/ok to test 1e45d9f

[achirkin]

/merge