Revert "add explicit handling for empty slices"

This reverts commit d0d616b.

Author: shuoweil

bigframes/core/rewrite/slices.py

@@ -76,17 +76,6 @@ def rewrite_slice(node: nodes.BigFrameNode):
         return node
 
     slice_def = (node.start, node.stop, node.step)
-
-    # Handle empty slice cases exlicitly (e.g. [0:0])
-    if (
-        node.start is not None
-        and node.stop is not None
-        and node.start >= node.stop
-        and (node.step is None or node.step > 0)
-    ):
-        # Return empty result by filtering with impossible condition
-        return slice_as_filter(node.child, node.start, node.start, node.step or 1)
-
     # no-op (eg. df[::1])
     if slices.is_noop(slice_def, node.child.row_count):
         return node.child