Only convert to totalAvgSeconds once

When serializing Duration we write totalAvgSeconds. But when we read
we converted to totalAvgSeconds again as if we had read seconds.
This would make read Durations look bigger than they actually where and
screw up comparisons.

community/kernel/src/main/java/org/neo4j/kernel/impl/index/schema/GenericKeyState.java

@@ -963,7 +963,7 @@ private void readDuration( PageCursor cursor )
         int nanosOfSecond = cursor.getInt();
         long months = cursor.getLong();
         long days = cursor.getLong();
-        writeDuration( months, days, totalAvgSeconds, nanosOfSecond );
+        writeDurationWithTotalAvgSeconds( months, days, totalAvgSeconds, nanosOfSecond );
     }
 
     private void readLocalTime( PageCursor cursor )
@@ -1251,18 +1251,24 @@ public void writeString( char value ) throws RuntimeException
 
     @Override
     public void writeDuration( long months, long days, long seconds, int nanos )
+    {
+        long totalAvgSeconds = months * AVG_MONTH_SECONDS + days * AVG_DAY_SECONDS + seconds;
+        writeDurationWithTotalAvgSeconds( months, days, totalAvgSeconds, nanos );
+    }
+
+    private void writeDurationWithTotalAvgSeconds( long months, long days, long totalAvgSeconds, int nanos )
     {
         if ( !isArray )
         {
             type = Type.DURATION;
-            long0 = months * AVG_MONTH_SECONDS + days * AVG_DAY_SECONDS + seconds;
+            long0 = totalAvgSeconds;
             long1 = nanos;
             long2 = months;
             long3 = days;
         }
         else
         {
-            long0Array[currentArrayOffset] = months * AVG_MONTH_SECONDS + days * AVG_DAY_SECONDS + seconds;
+            long0Array[currentArrayOffset] = totalAvgSeconds;
             long1Array[currentArrayOffset] = nanos;
             long2Array[currentArrayOffset] = months;
             long3Array[currentArrayOffset] = days;