When using StandardArtifactManager, fall back to original implementation of getFile which does not require a temporary file.
Necessary to avoid a temp file leak when using the CloudBees Deployer plugin, especially the Deploy Now column.
Site build tests are currently timing out for me; do not fail the test case in this situation.
Make the $job/site link behave sanely when target/site/index.html is missing (perhaps due to maven-site-plugin failure).