Use linkedhashmap for P-Chain mempool

vms/platformvm/block/builder/builder.go

@@ -270,7 +270,7 @@ func buildBlock(
 	}
 
 	// Clean out the mempool's transactions with invalid timestamps.
-	droppedStakerTxIDs := mempool.DropExpiredStakerTxs(builder.Mempool, timestamp.Add(txexecutor.SyncBound))
+	droppedStakerTxIDs := builder.Mempool.DropExpiredStakerTxs(timestamp.Add(txexecutor.SyncBound))
 	for _, txID := range droppedStakerTxIDs {
 		builder.txExecutorBackend.Ctx.Log.Debug("dropping tx",
 			zap.Stringer("txID", txID),

vms/platformvm/block/builder/builder_test.go

@@ -401,7 +401,7 @@ func TestBuildBlock(t *testing.T) {
 				mempool := mempool.NewMockMempool(ctrl)
 
 				// There are txs.
-				mempool.EXPECT().HasStakerTx().Return(false)
+				mempool.EXPECT().DropExpiredStakerTxs(gomock.Any()).Return([]ids.ID{})
 				mempool.EXPECT().HasTxs().Return(true)
 				mempool.EXPECT().PeekTxs(targetBlockSize).Return(transactions)
 				return &builder{
@@ -448,7 +448,7 @@ func TestBuildBlock(t *testing.T) {
 				mempool := mempool.NewMockMempool(ctrl)
 
 				// There are no txs.
-				mempool.EXPECT().HasStakerTx().Return(false)
+				mempool.EXPECT().DropExpiredStakerTxs(gomock.Any()).Return([]ids.ID{})
 				mempool.EXPECT().HasTxs().Return(false)
 
 				clk := &mockable.Clock{}
@@ -496,7 +496,7 @@ func TestBuildBlock(t *testing.T) {
 				mempool := mempool.NewMockMempool(ctrl)
 
 				// There are no txs.
-				mempool.EXPECT().HasStakerTx().Return(false)
+				mempool.EXPECT().DropExpiredStakerTxs(gomock.Any()).Return([]ids.ID{})
 				mempool.EXPECT().HasTxs().Return(false)
 				mempool.EXPECT().PeekTxs(targetBlockSize).Return(nil)
 
@@ -551,7 +551,7 @@ func TestBuildBlock(t *testing.T) {
 				mempool := mempool.NewMockMempool(ctrl)
 
 				// There is a tx.
-				mempool.EXPECT().HasStakerTx().Return(false)
+				mempool.EXPECT().DropExpiredStakerTxs(gomock.Any()).Return([]ids.ID{})
 				mempool.EXPECT().HasTxs().Return(true)
 				mempool.EXPECT().PeekTxs(targetBlockSize).Return([]*txs.Tx{transactions[0]})
 
@@ -605,7 +605,7 @@ func TestBuildBlock(t *testing.T) {
 
 				// There are no decision txs
 				// There is a staker tx.
-				mempool.EXPECT().HasStakerTx().Return(false)
+				mempool.EXPECT().DropExpiredStakerTxs(gomock.Any()).Return([]ids.ID{})
 				mempool.EXPECT().HasTxs().Return(true)
 				mempool.EXPECT().PeekTxs(targetBlockSize).Return([]*txs.Tx{transactions[0]})