Backport of Test: add noCleanup to TestServer stop into release/1.15.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #16919 to be assessed for backporting due to the inclusion of the label backport/1.15.

The below text is copied from the body of the original PR.

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Description

noCleanup exists in the test code to preserve the data after unit test run.

consul/sdk/testutil/io.go

Line 12 in 430df05

var noCleanup = strings.ToLower(os.Getenv("TEST_NOCLEANUP")) == "true"

noCleanup has been used in someplace like

consul/sdk/testutil/io.go

Line 18 in 430df05

func TempDir(t testing.TB, name string) string {

PR Checklist

• updated test coverage
• external facing docs updated
• not a security concern

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Overview of commits

• 9862a83

[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR