More info: go/immutable-map-buildorthrow-lsc NOTE: if the source of truth for this code is *NOT* `third_party`, please let me know and I'll revert this CL (and please consider upstreaming this change yourself). #inlineme Tested: TAP for global presubmit queue passed after automated deflaking of failures: http://mondo/deflaker/run/530857d2-45cb-4069-a234-48c5efe945f1 http://mondo/deflaker/run/0dce4296-e6bb-42d2-8b64-b393f45b6ad3 http://test/OCL:425453729:BASE:425451020:1643699365244:811c1a24 PiperOrigin-RevId: 425616165
