ClangRefactoring: Add WAL checkpoint at the end of the symbol storage

Change-Id: I70fde54947a302ae0e45bff083cd5654c86b3891
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/tools/clangrefactoringbackend/source/symbolstorage.h

@@ -54,6 +54,7 @@ public:
         , database(database)
     {
         transaction.commit();
+        database.walCheckpointFull();
     }
 
     void addSymbolsAndSourceLocations(const SymbolEntries &symbolEntries,