Remove mavenLocal() in the Gradle build script

[crazyzhou]

Problem description
When using gradle with mavenLocal(), there would be an issue like https://issues.gradle.org/browse/GRADLE-2034 and #309 that cannot resolve the test dependencies from the remote. It's better to remove the usage. There is a blog fully explaining how it works: https://medium.com/decisionbrain/when-to-not-use-mavenlocal-in-your-gradle-build-script-6da03902f9df

Problem location
build.gradle

Suggestions for an improvement