* Reland x2: Make GetDefaultEventEngine return a shared_ptr
* remove thread leak from NativeDNSResolver
This is not going to work for resolvers that support cancellation.
* give resolvers bounded lifetimes
Some resolver own EventEngines. EventEngines cannot run off the end of
the process since they have unjoined threads (problematic in a small set
of environments). This gives resolvers bounded lifetimes, and allows
replacement of resolvers without ASAN issues of deleting resolvers in
active use (occurs in tests).
* fix
* fix windows
* fix surface init test
* fix
* sanitize
* use after move
* the test must wait for the callback to be destroyed
* windows fix: delete the resolver on iomgr shutdown, not before
* Make TimerManager threads non-joinable
On gRPC shutdown, any unjoined TimerManager threads will cause TSAN to
detect thread leaks. This fix resolves issues I saw in end2end test
shutdown in another PR, where a single timer manager thread was always
alive after the test ended.
The long-term solution is to integrate the new ThreadPool here, but this
unblocks me for now.
* backport fix
* fix
* shared_ptr<EventEngine> in EventEngine benchmarks
AJ Heller