This ticket updates rounding functions in S2 geometry library to obey 'round to even' behavior across all platforms when generating geospatial index keys. Previously, ARM/non-x86 arches had followed 'round half up' semantics. As a result, non-x86 platforms which upgrade to a version which contains this patch may report extra geospatial index keys when the 'validate' command is run. These extra geospatial keys can be removed by rebuilding any effective indexes. Finally, note that once SERVER-77241 is implemented, this scenario will be detected and reported as part of the validate command.