netty: use composite cumulator for perf flamegraph tests

Author: sergiitk

alts/src/main/java/io/grpc/alts/internal/TsiFrameHandler.java

@@ -48,6 +48,7 @@ public final class TsiFrameHandler extends ByteToMessageDecoder implements Chann
 
   public TsiFrameHandler(TsiFrameProtector protector) {
     this.protector = checkNotNull(protector, "protector");
+    setCumulator(COMPOSITE_CUMULATOR);
   }
 
   @Override

alts/src/main/java/io/grpc/alts/internal/TsiHandshakeHandler.java

@@ -93,6 +93,7 @@ public TsiHandshakeHandler(
     this.handshaker = checkNotNull(handshaker, "handshaker");
     this.handshakeValidator = checkNotNull(handshakeValidator, "handshakeValidator");
     this.next = checkNotNull(next, "next");
+    setCumulator(COMPOSITE_CUMULATOR);
   }
 
   @Override
@@ -190,4 +191,4 @@ private void sendHandshake(ChannelHandlerContext ctx) throws GeneralSecurityExce
   protected void handlerRemoved0(ChannelHandlerContext ctx) throws Exception {
     handshaker.close();
   }
-}
+}

netty/src/main/java/io/grpc/netty/GrpcHttp2ConnectionHandler.java

@@ -42,6 +42,7 @@ protected GrpcHttp2ConnectionHandler(
       Http2Settings initialSettings) {
     super(decoder, encoder, initialSettings);
     this.channelUnused = channelUnused;
+    setCumulator(COMPOSITE_CUMULATOR);
   }
 
   /**