[SPARK-14462][ML][MLLIB] Add the mllib-local build to maven pom

## What changes were proposed in this pull request?

In order to separate the linear algebra, and vector matrix classes into a standalone jar, we need to setup the build first. This PR will create a new jar called mllib-local with minimal dependencies.

The previous PR was failing the build because of `spark-core:test` dependency, and that was reverted. In this PR, `FunSuite` with `// scalastyle:ignore funsuite` in mllib-local test was used, similar to sketch.

Thanks.

## How was this patch tested?

Unit tests

mengxr tedyu holdenk

Author: DB Tsai <dbt@netflix.com>

Closes #12298 from dbtsai/dbtsai-mllib-local-build-fix.

2 files changed, 51 insertions, 0 deletions

diff --git a/mllib-local/src/main/scala/org/apache/spark/ml/DummyTesting.scala b/mllib-local/src/main/scala/org/apache/spark/ml/DummyTesting.scala
new file mode 100644
index 0000000000..6b3268cdfa
--- /dev/null
+++ b/mllib-local/src/main/scala/org/apache/spark/ml/DummyTesting.scala
@@ -0,0 +1,23 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.ml
+
+// This is a private class testing if the new build works. To be removed soon.
+private[ml] object DummyTesting {
+  private[ml] def add10(input: Double): Double = input + 10
+}
diff --git a/mllib-local/src/test/scala/org/apache/spark/ml/DummyTestingSuite.scala b/mllib-local/src/test/scala/org/apache/spark/ml/DummyTestingSuite.scala
new file mode 100644
index 0000000000..51b7c2409f
--- /dev/null
+++ b/mllib-local/src/test/scala/org/apache/spark/ml/DummyTestingSuite.scala
@@ -0,0 +1,28 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.ml
+
+import org.scalatest.FunSuite // scalastyle:ignore funsuite
+
+// This is testing if the new build works. To be removed soon.
+class DummyTestingSuite extends FunSuite { // scalastyle:ignore funsuite
+
+  test("This is testing if the new build works.") {
+    assert(DummyTesting.add10(15) === 25)
+  }
+}