Fix literal handling for views of empty Aggregates (backport #4071) (#4074)

* Fix literal handling for views of empty Aggregates (#4071)

Previously, a view of an empty Record or Vec would always have a
litValue of 0.

(cherry picked from commit 11c3f51c

)

# Conflicts:
#	src/test/scala/chiselTests/experimental/DataView.scala

* Fixup backport conflicts

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Co-authored-by: Jack Koenig <koenig@sifive.com>