Make transaction queue order deterministic:

* Sort by fee level (which is the current behavior) then by transaction
  ID (hash).
* Edge case when the account at the end of the queue submits a higher
  paying transaction to walk backwards and compare against the cheapest
  transaction from a different account.
* Use std::if_any to simplify the JobQueue::isOverloaded loop.

src/ripple/core/impl/JobQueue.cpp

@@ -168,13 +168,9 @@ JobQueue::addLoadEvents(JobType t, int count, std::chrono::milliseconds elapsed)
 bool
 JobQueue::isOverloaded()
 {
-    for (auto& x : m_jobData)
-    {
-        if (x.second.load().isOver())
-            return true;
-    }
-
-    return false;
+    return std::any_of(m_jobData.begin(), m_jobData.end(), [](auto& entry) {
+        return entry.second.load().isOver();
+    });
 }
 
 Json::Value