Goroutine leak of WaitForStateChange

[JmPotato]

goleak: Errors on successful test run: found unexpected goroutines:
[Goroutine 357 in state select, with google.golang.org/grpc.(*ClientConn).WaitForStateChange on top of the stack:
goroutine 357 [select]:
google.golang.org/grpc.(*ClientConn).WaitForStateChange(0xc0004d0a00, {0x172af48, 0xc0001de540}, 0x4)
	/home/runner/go/pkg/mod/google.golang.org/[email protected]/clientconn.go:512 +0x113
github.com/tikv/client-go/v2/internal/client.(*batchCommandsClient).waitConnReady(0xc000201080)
	/home/runner/work/client-go/client-go/internal/client/client_batch.go:558 +0x248
github.com/tikv/client-go/v2/internal/client.(*batchCommandsClient).initBatchClient(0xc000201080, {0x0, 0x0})
	/home/runner/work/client-go/client-go/internal/client/client_batch.go:726 +0xda
github.com/tikv/client-go/v2/internal/client.(*batchCommandsClient).send(0xc000201080, {0x0, 0x0}, 0xc00010f130)
	/home/runner/work/client-go/client-go/internal/client/client_batch.go:503 +0x73
github.com/tikv/client-go/v2/internal/client.(*batchConn).getClientAndSend(0xc00057c780)
	/home/runner/work/client-go/client-go/internal/client/client_batch.go:381 +0x3ca
github.com/tikv/client-go/v2/internal/client.(*batchConn).batchSendLoop(0xc00057c780, {0x4, 0xa, 0x3, {0x1570c3b, 0x4}, {0x1570366, 0x3}, {0x100, 0x1000, ...}, ...})
	/home/runner/work/client-go/client-go/internal/client/client_batch.go:344 +0xda
created by github.com/tikv/client-go/v2/internal/client.(*connArray).Init
	/home/runner/work/client-go/client-go/internal/client/client.go:232 +0x1dff

]
FAIL	github.com/tikv/client-go/v2/internal/locate	26.400s

Ref: https://github.com/tikv/client-go/runs/8183462912?check_suite_focus=true