Racy test: Test/UnixCustomDialer

[easwars]

https://github.com/grpc/grpc-go/pull/4813/checks?check_run_id=3702858717

==================
WARNING: DATA RACE
Read at 0x00c0001f0043 by goroutine 1585:
  testing.(*common).logDepth()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:768 +0xc4
  testing.(*common).log()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:761 +0x5a
  testing.(*common).Log()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:800 +0x14
  google.golang.org/grpc/internal/grpctest.(*tLogger).log()
      /home/runner/work/grpc-go/grpc-go/internal/grpctest/tlogger.go:116 +0x4c4
  google.golang.org/grpc/internal/grpctest.(*tLogger).InfoDepth()
      /home/runner/work/grpc-go/grpc-go/internal/grpctest/tlogger.go:210 +0x64
  google.golang.org/grpc/internal/grpclog.InfoDepth()
      /home/runner/work/grpc-go/grpc-go/internal/grpclog/grpclog.go:35 +0x85
  google.golang.org/grpc/grpclog.(*componentData).InfoDepth()
      /home/runner/work/grpc-go/grpc-go/grpclog/component.go:36 +0x1b2
  google.golang.org/grpc/grpclog.(*componentData).Infof()
      /home/runner/work/grpc-go/grpc-go/grpclog/component.go:71 +0x1d
  google.golang.org/grpc/internal/channelz.(*dummyEntry).deleteChild()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:68 +0x128
  google.golang.org/grpc/internal/channelz.(*subChannel).deleteSelfFromTree()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:357 +0x2e5
  google.golang.org/grpc/internal/channelz.(*subChannel).deleteSelfIfReady()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:389 +0x30
  google.golang.org/grpc/internal/channelz.(*channelMap).decrTraceRefCount()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/funcs.go:389 +0x275
  google.golang.org/grpc/internal/channelz.(*channelTrace).clear()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:663 +0xf8
  google.golang.org/grpc/internal/channelz.(*channel).deleteSelfIfReady()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:288 +0x284
  google.golang.org/grpc/internal/channelz.(*channel).deleteChild()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:224 +0x88
  google.golang.org/grpc/internal/channelz.(*subChannel).deleteSelfFromTree()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:357 +0x2e5
  google.golang.org/grpc/internal/channelz.(*subChannel).deleteSelfIfReady()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:389 +0x30
  google.golang.org/grpc/internal/channelz.(*subChannel).deleteChild()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:334 +0x5b
  google.golang.org/grpc/internal/channelz.(*normalSocket).triggerDelete()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/types.go:533 +0x4e1
  google.golang.org/grpc/internal/channelz.(*channelMap).removeEntry()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/funcs.go:380 +0x214
  google.golang.org/grpc/internal/channelz.RemoveEntry()
      /home/runner/work/grpc-go/grpc-go/internal/channelz/funcs.go:283 +0x3a
  google.golang.org/grpc/internal/transport.(*http2Client).Close()
      /home/runner/work/grpc-go/grpc-go/internal/transport/http2_client.go:893 +0x24b
  google.golang.org/grpc/internal/transport.(*http2Client).reader()
      /home/runner/work/grpc-go/grpc-go/internal/transport/http2_client.go:1518 +0xf3a
  google.golang.org/grpc/internal/transport.newHTTP2Client·dwrap·7()
      /home/runner/work/grpc-go/grpc-go/internal/transport/http2_client.go:355 +0x39

Previous write at 0x00c0001f0043 by goroutine 878:
  testing.tRunner.func1()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:1246 +0x584
  testing.tRunner()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:1265 +0x268
  testing.(*T).Run·dwrap·21()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:1306 +0x47

Goroutine 1585 (running) created at:
  google.golang.org/grpc/internal/transport.newHTTP2Client()
      /home/runner/work/grpc-go/grpc-go/internal/transport/http2_client.go:355 +0x265b
  google.golang.org/grpc/internal/transport.NewClientTransport()
      /home/runner/work/grpc-go/grpc-go/internal/transport/transport.go:576 +0x80a
  google.golang.org/grpc.(*addrConn).createTransport()
      /home/runner/work/grpc-go/grpc-go/clientconn.go:1322 +0x5a9
  google.golang.org/grpc.(*addrConn).tryAllAddrs()
      /home/runner/work/grpc-go/grpc-go/clientconn.go:1255 +0x4f8
  google.golang.org/grpc.(*addrConn).resetTransport()
      /home/runner/work/grpc-go/grpc-go/clientconn.go:1190 +0x20a
  google.golang.org/grpc.(*addrConn).connect()
      /home/runner/work/grpc-go/grpc-go/clientconn.go:868 +0xbb
  google.golang.org/grpc.(*acBalancerWrapper).Connect·dwrap·9()
      /home/runner/work/grpc-go/grpc-go/balancer_conn_wrappers.go:285 +0x39

Goroutine 878 (finished) created at:
  testing.(*T).Run()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:1306 +0x726
  google.golang.org/grpc/internal/grpctest.RunSubTests()
      /home/runner/work/grpc-go/grpc-go/internal/grpctest/grpctest.go:99 +0x54a
  google.golang.org/grpc/test.Test()
      /home/runner/work/grpc-go/grpc-go/test/end2end_test.go:90 +0x3c
  testing.tRunner()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:1259 +0x22f
  testing.(*T).Run·dwrap·21()
      /opt/hostedtoolcache/go/1.17.1/x64/src/testing/testing.go:1306 +0x47
==================