remove benchmark tests

At this point, we don't really care about mplex's performance any more.

To move forward with our repo consolidation effort, this package cannot depend
on go-libp2p-testing.

go.mod

@@ -3,31 +3,14 @@ module github.com/libp2p/go-mplex
 require (
 	github.com/ipfs/go-log/v2 v2.5.0
 	github.com/libp2p/go-buffer-pool v0.0.2
-	github.com/libp2p/go-libp2p-testing v0.1.2-0.20200422005655-8775583591d8
 	github.com/multiformats/go-varint v0.0.6
 	go.uber.org/multierr v1.6.0
-	google.golang.org/grpc v1.28.1
 )
 
 require (
-	github.com/btcsuite/btcd v0.20.1-beta // indirect
-	github.com/gogo/protobuf v1.3.1 // indirect
-	github.com/ipfs/go-cid v0.0.3 // indirect
-	github.com/libp2p/go-libp2p-core v0.3.0 // indirect
-	github.com/libp2p/go-openssl v0.0.4 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
-	github.com/minio/blake2b-simd v0.0.0-20160723061019-3f5f724cb5b1 // indirect
-	github.com/minio/sha256-simd v0.1.1 // indirect
-	github.com/mr-tron/base58 v1.1.3 // indirect
-	github.com/multiformats/go-base32 v0.0.3 // indirect
-	github.com/multiformats/go-multiaddr v0.2.0 // indirect
-	github.com/multiformats/go-multibase v0.0.1 // indirect
-	github.com/multiformats/go-multihash v0.0.10 // indirect
-	github.com/spacemonkeygo/spacelog v0.0.0-20180420211403-2296661a0572 // indirect
-	github.com/spaolacci/murmur3 v1.1.0 // indirect
 	go.uber.org/atomic v1.7.0 // indirect
 	go.uber.org/zap v1.19.1 // indirect
-	golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 // indirect
 	golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c // indirect
 )