Main commit:
If one of the objects had invalid selected edges, it would lead to a crash since none of the for loops were checking for whether the edge slide data is valid. We could refactor the macros to create a new FOREACH_TRANS_DATA_CONTAINER_WITH_DATA However we are too close to 2.80 final release so we manually skip them for now. Note: TRANS_DATA_CONTAINER_FIRST_OK cannot be used either for the same reason.
Bonus commit:
Edge Slide: Fix multi-object for loop early exit