Resolves #3940.

The issue is that in our optimized implementation of foreachPar_ we are forking a fiber for each task and waiting for it to signal success or failure. But if an exception is thrown during the construction of the task this logic is never executed so we suspend indefinitely waiting for the signal.

This PR addresses by using effectSuspendTotal to convert thrown exceptions in constructing the task to fiber failures.

One slightly unfortunate thing is that now there is a slight asymmetry between foreach and foreachPar in that ZIO.foreach(as)(f).run will fail with a fiber failure if f throwsbutZIO.foreachPar(as)(f).run` will return an exit with a die failure..