Fixes #1186 limit the number of items in the ThreadLocal list in the ConcurrentBag.

src/main/java/com/zaxxer/hikari/util/ConcurrentBag.java

@@ -195,8 +195,10 @@ public class ConcurrentBag<T extends IConcurrentBagEntry> implements AutoCloseab
       }
 
       final List<Object> threadLocalList = threadList.get();
+      if (threadLocalList.size() < 50) {
          threadLocalList.add(weakThreadLocals ? new WeakReference<>(bagEntry) : bagEntry);
       }
+   }
 
    /**
     * Add a new object to the bag for others to borrow.