TestMiddlewareTestSuite is unstable

[lhy1024]

Flaky Test

Which jobs are failing

2024-08-09T09:16:08.8855215Z     suite.go:87: test panicked: runtime error: invalid memory address or nil pointer dereference
2024-08-09T09:16:08.8856405Z         goroutine 1943 [running]:
2024-08-09T09:16:08.8857063Z         runtime/debug.Stack()
2024-08-09T09:16:08.8858131Z         	/opt/hostedtoolcache/go/1.21.12/x64/src/runtime/debug/stack.go:24 +0x67
2024-08-09T09:16:08.8859587Z         github.com/stretchr/testify/suite.failOnPanic(0xc008b7e1a0, {0x4438340, 0x6afdd90})
2024-08-09T09:16:08.8861256Z         	/home/runner/go/pkg/mod/github.com/stretchr/[email protected]/suite/suite.go:87 +0x4e
2024-08-09T09:16:08.8862517Z         github.com/stretchr/testify/suite.Run.func1.1()
2024-08-09T09:16:08.8863920Z         	/home/runner/go/pkg/mod/github.com/stretchr/[email protected]/suite/suite.go:183 +0x345
2024-08-09T09:16:08.8865038Z         panic({0x4438340?, 0x6afdd90?})
2024-08-09T09:16:08.8866130Z         	/opt/hostedtoolcache/go/1.21.12/x64/src/runtime/panic.go:920 +0x270
2024-08-09T09:16:08.8867260Z         github.com/tikv/pd/tests.(*TestServer).GetServer(0x0)
2024-08-09T09:16:08.8868288Z         	/home/runner/work/pd/pd/tests/cluster.go:217 +0x85
2024-08-09T09:16:08.8869774Z         github.com/tikv/pd/tests/server/api.(*middlewareTestSuite).TestRateLimitMiddleware(0xc0001ac320)
2024-08-09T09:16:08.8873022Z         	/home/runner/work/pd/pd/tests/server/api/api_test.go:304 +0x1a32
2024-08-09T09:16:08.8874616Z         reflect.Value.call({0xc0010dbfc0?, 0xc0065a9c78?, 0x13?}, {0x4782a5e, 0x4}, {0xc008e47db0, 0x1, 0x1?})
2024-08-09T09:16:08.8876195Z         	/opt/hostedtoolcache/go/1.21.12/x64/src/reflect/value.go:596 +0x14ce
2024-08-09T09:16:08.8877705Z         reflect.Value.Call({0xc0010dbfc0?, 0xc0065a9c78?, 0xc0001ac320?}, {0xc005fb4db0, 0x1, 0x1})
2024-08-09T09:16:08.8879210Z         	/opt/hostedtoolcache/go/1.21.12/x64/src/reflect/value.go:380 +0xb6
2024-08-09T09:16:08.8880357Z         github.com/stretchr/testify/suite.Run.func1(0xc008b7e1a0)
2024-08-09T09:16:08.8882282Z         	/home/runner/go/pkg/mod/github.com/stretchr/[email protected]/suite/suite.go:197 +0x767
2024-08-09T09:16:08.8883493Z         testing.tRunner(0xc008b7e1a0, 0xc001342990)
2024-08-09T09:16:08.8884767Z         	/opt/hostedtoolcache/go/1.21.12/x64/src/testing/testing.go:1595 +0x262
2024-08-09T09:16:08.8885830Z         created by testing.(*T).Run in goroutine 255
2024-08-09T09:16:08.8887022Z         	/opt/hostedtoolcache/go/1.21.12/x64/src/testing/testing.go:1648 +0x846
2024-08-09T09:16:08.8888020Z === RUN   TestMiddlewareTestSuite/TestRequestInfoMiddleware
2024-08-09T09:16:08.8888814Z     api_test.go:143: 
2024-08-09T09:16:08.8889865Z         	Error Trace:	/home/runner/work/pd/pd/tests/server/api/api_test.go:143
2024-08-09T09:16:08.8891022Z         	Error:      	Expected value not to be nil.
2024-08-09T09:16:08.8892135Z         	Test:       	TestMiddlewareTestSuite/TestRequestInfoMiddleware
2024-08-09T09:16:08.8893339Z === RUN   TestMiddlewareTestSuite/TestSwaggerUrl
2024-08-09T09:16:08.8894086Z     api_test.go:393: 
2024-08-09T09:16:08.8895167Z         	Error Trace:	/home/runner/work/pd/pd/tests/server/api/api_test.go:393
2024-08-09T09:16:08.8896262Z         	Error:      	Expected value not to be nil.
2024-08-09T09:16:08.8897220Z         	Test:       	TestMiddlewareTestSuite/TestSwaggerUrl

CI link

https://github.com/tikv/pd/actions/runs/10316739856/job/28559587719
https://github.com/tikv/pd/actions/runs/10314613258/job/28553316701

Reason for failure (if possible)

Anything else