This commit provides opt-in enablement of Gradle's remote build
cache. When the GRADLE_ENTERPRISE_URL environment variable is set, its
build cache node will be used as a source of cached output. If both
GRADLE_ENTERPRISE_CACHE_USERNAME and GRADLE_ENTERPRISE_CACHE_PASSWORD
are also set, task output produced by the build will be pushed to the
build cache node for use by subsequent builds.
Closes gh-23883
Andy Wilkinson
Sam Brannen
Johnny Lim