[CASDB] OnDiskCAS should not create LeafNode when node has refs#4660

cachemeifyoucan merged 2 commits intoswiftlang:experimental/cas/mainswiftlang/llvm-project:experimental/cas/mainfrom

cachemeifyoucan:eng/PR-large-node-refscachemeifyoucan/llvm-project:eng/PR-large-node-refsCopy head branch name to clipboard