Synchronize Gradle wrappers among builds

[dmdashenkov]

Now that we have custom pull scripts (see #534), we can sync the Gradle wrapper configs and JARs automatically upon pull instead of manually updating ./gradle/wrapper, ./tools/smoke-tests/gradle/wrapper, and ./base-validating-builders/gradle/wrapper.

[alexander-yevsyukov]

This issue relates to #578.

[alexander-yevsyukov]

No longer relevant to this repo and is addressed in mc-java.