Contains a number of optimizations that improve the Subzero coroutine performance up to 10x.

Changes:
    ca8408f68 Scheduler: Reduce the number of mutex locks / unlock.
    575b61e76 Fix compilation of marl::Ticket::onCall()
    e9f312688 waitForWork(): Early out if there work.num > 0
    3196a0539 Scheduler: Use std::deque instead of std::queue
    08a820171 Add flags to marl::Task
    cb3c481d0 Scheduler: Use a separate flag to indicate whether to call notify()
    598c993ec marl::ConditionVariable - use containers::list
    d0c501a9c Add marl::containers::list
    aa1de9091 Benchmarks: Add EventBaton

Commands:
    git subtree pull --prefix third_party/marl https://github.com/google/marl master --squash

Bug: b/140546382
Change-Id: I2b7adc3c624a1f3aef686de7e0e88c52a5666e3a