e2e: weight protocol dimensions (#6884)

This changes the focus of the e2e suite, to (roughly) focus on
configurations that are more well used. Most production users of
tendermint run ABCI application in process and the GRPC/socket methods
cover the vast majority of the remaining use cases. 

Perhaps we should consider drop support unix domain sockets in a
future release, but I think in the mean time it's useful to have the
tests *mostly* focus on the primary use cases.

test/e2e/generator/generate.go

@@ -33,8 +33,18 @@ var (
 		"rocksdb":   10,
 		"cleveldb":  5,
 	}
-	nodeABCIProtocols    = uniformChoice{"unix", "tcp", "builtin", "grpc"}
-	nodePrivvalProtocols = uniformChoice{"file", "unix", "tcp", "grpc"}
+	nodeABCIProtocols = weightedChoice{
+		"builtin": 50,
+		"tcp":     20,
+		"grpc":    20,
+		"unix":    10,
+	}
+	nodePrivvalProtocols = weightedChoice{
+		"file": 50,
+		"grpc": 20,
+		"tcp":  20,
+		"unix": 10,
+	}
 	// FIXME: v2 disabled due to flake
 	nodeBlockSyncs        = uniformChoice{"v0"} // "v2"
 	nodeMempools          = uniformChoice{"v0", "v1"}
@@ -277,8 +287,8 @@ func generateNode(
 		Mode:             string(mode),
 		StartAt:          startAt,
 		Database:         nodeDatabases.Choose(r),
-		ABCIProtocol:     nodeABCIProtocols.Choose(r).(string),
-		PrivvalProtocol:  nodePrivvalProtocols.Choose(r).(string),
+		ABCIProtocol:     nodeABCIProtocols.Choose(r),
+		PrivvalProtocol:  nodePrivvalProtocols.Choose(r),
 		BlockSync:        nodeBlockSyncs.Choose(r).(string),
 		Mempool:          nodeMempools.Choose(r).(string),
 		StateSync:        nodeStateSyncs.Choose(r).(bool) && startAt > 0,