backport to 1.16: test: avoid use after free in oauth_integration_test (#14103)#14109

antoniovicente wants to merge 1 commit intoenvoyproxy:release/v1.16envoyproxy/envoy:release/v1.16from

antoniovicente:deflake_oauth_integration_test_v1.16antoniovicente/envoy:deflake_oauth_integration_test_v1.16Copy head branch name to clipboard