Right now all of the SDI write ops are one-shot operations. This makes it difficult for storage engines such as wiredtiger that are able to reduce duplicated work when a cursor is used to insert many kv pairs into the same tree. While this doesn't matter much for simple indexes that may only have 1 or a handful of entries per document per index, it can be a real problem for wildcard where there can be hundreds of entrees per document per index.

This change would also stack nicely with propagating bulk insertion from the Collection layer to the IndexCatalog layer (SERVER-55338), since it will increase the probability of inserting keys that are close together, taking advantage of less btree lookup.