This implementation may at some point become the default on some
platforms.  Currently not all platforms have widespread support for
both real absolute timeouts or real relative timeouts (here "real"
means without converting to the other timeout type which is the only
one supported by the underlying APIs). In this case we can defer to
their standard library to implement correct support.

This is not currently the default on any platform

Note: The size of WaiterState had to increase to fit the new implementation
PiperOrigin-RevId: 518266646
Change-Id: I7f246646a960d6e1b155f9de0bf2f681c5d3d245