Rollup merge of #140210 - Berrysoft:cygwin-timedwait, r=joboet

Work around cygwin issue on condvar timeout

This workaround *just works*... Actually I don't quite understand why does it work in such way. With a simple test on Cygwin, it seems that the maximum value of `tv_sec` could be 12899331056917, while the maximum value of `tv_nsec` should be a value floating around 464600000. A larger `timespec` could block the syscall forever.

r? `@joboet`

Author: matthiaskrgr