go leak in pd http client and some tests

[HuSharp]

Bug Report

What did you do?

remove goleak.IgnoreTopFunction("internal/poll.runtime_pollWait") and run test

What did you expect to see?

no leak

What did you see instead?

goleak: Errors on successful test run: found unexpected goroutines:
[Goroutine 323 in state IO wait, with internal/poll.runtime_pollWait on top of the stack:
internal/poll.runtime_pollWait(0x12fa839f0, 0x72)
        /opt/homebrew/opt/go/libexec/src/runtime/netpoll.go:343 +0xa0
internal/poll.(*pollDesc).wait(0x14000ba4c80?, 0x14000c60000?, 0x0)
        /opt/homebrew/opt/go/libexec/src/internal/poll/fd_poll_runtime.go:84 +0x28
internal/poll.(*pollDesc).waitRead(...)
        /opt/homebrew/opt/go/libexec/src/internal/poll/fd_poll_runtime.go:89
internal/poll.(*FD).Read(0x14000ba4c80, {0x14000c60000, 0x8000, 0x8000})
        /opt/homebrew/opt/go/libexec/src/internal/poll/fd_unix.go:164 +0x200
net.(*netFD).Read(0x14000ba4c80, {0x14000c60000?, 0x14000a03c68?, 0x10401?})
        /opt/homebrew/opt/go/libexec/src/net/fd_posix.go:55 +0x28
net.(*conn).Read(0x14000998188, {0x14000c60000?, 0x14000a03d48?, 0x104d17a74?})
        /opt/homebrew/opt/go/libexec/src/net/net.go:179 +0x34
bufio.(*Reader).Read(0x140009ab320, {0x140001a0e40, 0x9, 0x140009d4f30?})
        /opt/homebrew/opt/go/libexec/src/bufio/bufio.go:244 +0x1b4
io.ReadAtLeast({0x1065d26d8, 0x140009ab320}, {0x140001a0e40, 0x9, 0x9}, 0x9)
        /opt/homebrew/opt/go/libexec/src/io/io.go:335 +0xa0
io.ReadFull(...)
        /opt/homebrew/opt/go/libexec/src/io/io.go:354
golang.org/x/net/http2.readFrameHeader({0x140001a0e40, 0x9, 0x140009d4f60?}, {0x1065d26d8?, 0x140009ab320?})
        /Users/pingcap/go/pkg/mod/golang.org/x/net@v0.20.0/http2/frame.go:237 +0x58
golang.org/x/net/http2.(*Framer).ReadFrame(0x140001a0e00)
        /Users/pingcap/go/pkg/mod/golang.org/x/net@v0.20.0/http2/frame.go:498 +0x78
google.golang.org/grpc/internal/transport.(*http2Client).reader(0x140009d26c0, 0x0?)
        /Users/pingcap/go/pkg/mod/google.golang.org/grpc@v1.60.1/internal/transport/http2_client.go:1587 +0x1b8
created by google.golang.org/grpc/internal/transport.newHTTP2Client in goroutine 314
        /Users/pingcap/go/pkg/mod/google.golang.org/grpc@v1.60.1/internal/transport/http2_client.go:398 +0x1640
 Goroutine 120 in state IO wait, with internal/poll.runtime_pollWait on top of the stack:
internal/poll.runtime_pollWait(0x12fa83be0, 0x72)

What version of PD are you using (pd-server -V)?

master