remove thread local recycler

the thread local recycler requires obtain and recycle to be called on the same thread, while other recyclers do not. Also, it can create heavy recycle usage since it depends on the threads that its being used on. The concurrent / pinned thread base one is by far better than the pure thread local (and is the default) one since it more easily bounds the elements recycled, while still allowing to mix obtain and recycle across threads.

We will end up using the paged recyclers more and more, for example, in our networking output buffer, where obtaining will happen on one thread, while recycling can potentially occur on another thread (the callback thread). Since the limit of binding to a thread of the 2 calls is not really needed, and our best implementation supports going cross threads, there is no real need to impose this restriction.
Remove nanoTime in global cluster randomization in favor of deriving the
seed from the main master seed. Removed shared cluster's seed entirely.

The problem here is that if you don't give cluster's seed then test times
fluctuate oddly, even for a fixed -Dtests.seed=... This shouldn't be the
case -- ideally, the test ran with the same master seed should reproduce
pretty much with the same execution time (and internal logic, obviously).

From the code point of view "global" variables are indeed a problem
because JUnit has no notion of before-suite hooks. And RandomizedRunner
doesn't support context accesses in static class initializers (this is
intentional because there is no way to determine when such initializers
will be executed). A workaround is to move such static global variables to
lazily-initialized methods and invoke them (once) in @BeforeClass hooks.