Add randomness to port selection allowing running concurrent e2e tests

[serathius]

Useful for using stress to deflake test.

cc @ahrtr @siyuanfoundation @fuweid

[siyuanfoundation]

/retest

[fuweid]

2024-08-01T20:05:59.8946831Z {"Time":"2024-08-01T20:05:59.88891373Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"/home/runner/work/etcd/etcd/bin/etcdctl (/home/runner/work/etcd/etcd/bin/etcdctl_--endpoints=http://localhost:28121_--dial-timeout=7s_get_--write-out=protobuf_abc) (17766): \u0003abc\u0010\u0002\u0018\u0002 \u0001*\u0003123 \u0001    ctl_v3_kv_test.go:189: \n"}
2024-08-01T20:05:59.8949859Z {"Time":"2024-08-01T20:05:59.888928738Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"        \tError Trace:\t/home/runner/work/etcd/etcd/tests/e2e/ctl_v3_kv_test.go:189\n"}
2024-08-01T20:05:59.8951807Z {"Time":"2024-08-01T20:05:59.888933046Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"        \t            \t\t\t\t/home/runner/work/etcd/etcd/tests/e2e/ctl_v3_test.go:263\n"}
2024-08-01T20:05:59.8953847Z {"Time":"2024-08-01T20:05:59.888936332Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"        \t            \t\t\t\t/opt/hostedtoolcache/go/1.22.5/x64/src/runtime/asm_amd64.s:1695\n"}
2024-08-01T20:05:59.8956669Z {"Time":"2024-08-01T20:05:59.888940179Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"        \tError:      \t\"\\r\\n\\n\\x19\\bĭ\\xd4\\xf1ֹ\\xe6\\xa7\\xe7\\x01\\x10\\xec\\xbeÚ\\xef\\x9e\\xd6\\xd6n\\x18\\x02 \\x02\\x12\\x10\\r\\n\\n\\x03abc\\x10\\x02\\x18\\x02 \\x01*\\x03123 \\x01\" does not contain \"\\x17\\b\\x93\\xe7\\xf6\\x93\\xd4ņ\\xe14\\x10\\xed\"\n"}
2024-08-01T20:05:59.8959108Z {"Time":"2024-08-01T20:05:59.888950779Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"        \tTest:       \tTestCtlV3GetFormat\n"}
2024-08-01T20:05:59.8960698Z {"Time":"2024-08-01T20:05:59.888955889Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"    ctl_v3_test.go:264: ---testFunc logic DONE\n"}
2024-08-01T20:05:59.8962404Z {"Time":"2024-08-01T20:05:59.8889619Z","Action":"output","Package":"go.etcd.io/etcd/tests/v3/e2e","Test":"TestCtlV3GetFormat","Output":"    ctl_v3_test.go:275: closing test cluster...\n"}

[fuweid]

LGTM on green

Hopefully, we don't run into port confliction

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahrtr, fuweid, serathius, siyuanfoundation

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[henrybear327]

/retest

[k8s-ci-robot]

@serathius: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-etcd-e2e-386	8c93f8b	link	true	/test pull-etcd-e2e-386
pull-etcd-e2e-arm64	8c93f8b	link	true	/test pull-etcd-e2e-arm64
pull-etcd-e2e-amd64	8c93f8b	link	true	/test pull-etcd-e2e-amd64

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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