* add align for WorkQueue

* add spinlock

* merge develop

* merge

* Add EventsWaiter

* Revert "Add EventsWaiter"

This reverts commit e206173aa9be7401b83a53581627bfaf557c8fb2.

* add log for Executor

* Add CudaTracer to trace CUDA events
Co-authored-by: Nliutiexing <liutiexing@google.com>