[ThinLTO] Add missing breaks when parsing summaries (NFC)

This wasn't causing a correctness issue, but was causing extra duplicate
entries to be added to the SummaryMap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261757 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed