Remove windowStrategy deserialization exception handling

[kennknowles]

Remove the exception handling in JRH at

beam/runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/GroupAlsoByWindowParDoFnFactory.java

Line 106 in 98e553b

windowingStrategy = WindowingStrategy.globalDefault();

And subsequently fix Reshuffle transform to use _IdentityWindowFn in

beam/sdks/python/apache_beam/transforms/util.py

Line 626 in 98e553b

def restore_timestamps(element, window=DoFn.WindowParam):

 

Imported from Jira BEAM-8104. Original Jira may contain additional context.
Reported by: angoenka.