- trace system is now thread safe when run with TSAN
- fix a race in client_auth_filter.c
- allow timer manager to run in single threaded mode for fuzzers

This reverts commit 79759fea, reversing
changes made to dc36f4df.

(this needs more testing/analysis to prove that it's safe)

Switch from a lock free stack to an mpscq protected by a spinlock for incoming requests. The mpscq is unbounded and so needs (much) less memory allocated up front.
memory_profile_test shows this reduces initial server creation cost from 4MB to 1.5KB.

Changes required to make build possible: create separate grpc++_base{,_unsecure}, move grpc_compression_trace definition, and remove an assertion about library initialization from server

Move server startup to a separate thread.
Where there is no opportunity for failure, do not return bool.

Remove the check that ensures server completion queues are of type GRPC_CQ_NEXT (because ruby uses GRPC_CQ_PLUCK only)

large), add an error to the batch to avoid emitting new rpc on the
server side in C++.

This reverts commit 5e01e2ac.

- make closures know where they should be executed (eg, on a workqueue,
  or a combiner, or on an exec_ctx)
- this allows removal of a large number of trampoline functions that
  were appearing whenever we used combiners, and should allow for a much
  easier interface to combiner locks