Add tests for getCredentials with multiple goproxy_servers and maven_… #7543

Job	Run time
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.17.6)	1m 9s
Go: tracing with legacy workflow (ubuntu-latest, default)	1m 6s
Go: tracing with legacy workflow (macos-latest, nightly-latest)	4m 34s
Go: tracing with legacy workflow (ubuntu-latest, linked)	1m 10s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.21.4)	1m 15s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.18.4)	1m 21s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.20.7)	1m 26s
Go: tracing with legacy workflow (macos-latest, linked)	4m 30s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.22.4)	1m 20s
Go: tracing with legacy workflow (ubuntu-latest, stable-v2.19.4)	1m 24s
Go: tracing with legacy workflow (ubuntu-latest, nightly-latest)	1m 4s
	20m 19s

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