Remove AllocationService.reroute(ClusterState, String, boolean) (#44629)

This commit removes the method AllocationService.reroute(ClusterState, String, boolean) 
in favor of AllocationService.reroute(ClusterState, String).

Motivations are:
    there are already 3 other reroute methods in this class
    this method is always called with the debug parameter set to false
    almost all tests use the method reroute(ClusterState, String)

server/src/main/java/org/elasticsearch/cluster/routing/allocation/AllocationService.java

@@ -354,30 +354,19 @@ public CommandsResult reroute(final ClusterState clusterState, AllocationCommand
         return new CommandsResult(explanations, buildResultAndLogHealthChange(clusterState, allocation, "reroute commands"));
     }
 
-
     /**
      * Reroutes the routing table based on the live nodes.
      * <p>
      * If the same instance of ClusterState is returned, then no change has been made.
      */
     public ClusterState reroute(ClusterState clusterState, String reason) {
-        return reroute(clusterState, reason, false);
-    }
-
-    /**
-     * Reroutes the routing table based on the live nodes.
-     * <p>
-     * If the same instance of ClusterState is returned, then no change has been made.
-     */
-    protected ClusterState reroute(ClusterState clusterState, String reason, boolean debug) {
         ClusterState fixedClusterState = adaptAutoExpandReplicas(clusterState);
 
         RoutingNodes routingNodes = getMutableRoutingNodes(fixedClusterState);
         // shuffle the unassigned nodes, just so we won't have things like poison failed shards
         routingNodes.unassigned().shuffle();
         RoutingAllocation allocation = new RoutingAllocation(allocationDeciders, routingNodes, fixedClusterState,
             clusterInfoService.getClusterInfo(), currentNanoTime());
-        allocation.debugDecision(debug);
         reroute(allocation);
         if (fixedClusterState == clusterState && allocation.routingNodesChanged() == false) {
             return clusterState;

server/src/test/java/org/elasticsearch/cluster/routing/allocation/MaxRetryAllocationDeciderTests.java

@@ -72,7 +72,7 @@ private ClusterState createInitialClusterState() {
         clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")))
             .build();
         RoutingTable prevRoutingTable = routingTable;
-        routingTable = strategy.reroute(clusterState, "reroute", false).routingTable();
+        routingTable = strategy.reroute(clusterState, "reroute").routingTable();
         clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
 
         assertEquals(prevRoutingTable.index("idx").shards().size(), 1);
@@ -204,7 +204,7 @@ public void testFailedAllocation() {
                     Settings.builder().put(clusterState.metaData().index("idx").getSettings()).put("index.allocation.max_retries",
                         retries+1).build()
                 ).build(), true).build()).build();
-        ClusterState newState = strategy.reroute(clusterState, "settings changed", false);
+        ClusterState newState = strategy.reroute(clusterState, "settings changed");
         assertThat(newState, not(equalTo(clusterState)));
         clusterState = newState;
         routingTable = newState.routingTable();

server/src/test/java/org/elasticsearch/cluster/routing/allocation/ResizeAllocationDeciderTests.java

@@ -74,7 +74,7 @@ private ClusterState createInitialClusterState(boolean startShards) {
             ("node2", Version.CURRENT)))
             .build();
         RoutingTable prevRoutingTable = routingTable;
-        routingTable = strategy.reroute(clusterState, "reroute", false).routingTable();
+        routingTable = strategy.reroute(clusterState, "reroute").routingTable();
         clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
 
         assertEquals(prevRoutingTable.index("source").shards().size(), 2);