Add "full_outer" name to join types

I have discovered that "full_outer" name option is working in Spark 2.0, but it is not printed in exception. Please verify.

## What changes were proposed in this pull request?

(Please fill in changes proposed in this fix)

## How was this patch tested?

(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)
(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

Please review http://spark.apache.org/contributing.html before opening a pull request.

Author: BartekH <bartekhamielec@gmail.com>

Closes #17985 from BartekH/patch-1.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/joinTypes.scala

@@ -33,11 +33,11 @@ object JoinType {
     case _ =>
       val supported = Seq(
         "inner",
-        "outer", "full", "fullouter",
-        "leftouter", "left",
-        "rightouter", "right",
-        "leftsemi",
-        "leftanti",
+        "outer", "full", "fullouter", "full_outer",
+        "leftouter", "left", "left_outer",
+        "rightouter", "right", "right_outer",
+        "leftsemi", "left_semi",
+        "leftanti", "left_anti",
         "cross")
 
       throw new IllegalArgumentException(s"Unsupported join type '$typ'. " +

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/plans/JoinTypesTest.scala

+/*
+ * 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.sql.catalyst.plans
+
+import org.apache.spark.SparkFunSuite
+
+class JoinTypesTest extends SparkFunSuite {
+
+  test("construct an Inner type") {
+    assert(JoinType("inner") === Inner)
+  }
+
+  test("construct a FullOuter type") {
+    assert(JoinType("fullouter") === FullOuter)
+    assert(JoinType("full_outer") === FullOuter)
+    assert(JoinType("outer") === FullOuter)
+    assert(JoinType("full") === FullOuter)
+  }
+
+  test("construct a LeftOuter type") {
+    assert(JoinType("leftouter") === LeftOuter)
+    assert(JoinType("left_outer") === LeftOuter)
+    assert(JoinType("left") === LeftOuter)
+  }
+
+  test("construct a RightOuter type") {
+    assert(JoinType("rightouter") === RightOuter)
+    assert(JoinType("right_outer") === RightOuter)
+    assert(JoinType("right") === RightOuter)
+  }
+
+  test("construct a LeftSemi type") {
+    assert(JoinType("leftsemi") === LeftSemi)
+    assert(JoinType("left_semi") === LeftSemi)
+  }
+
+  test("construct a LeftAnti type") {
+    assert(JoinType("leftanti") === LeftAnti)
+    assert(JoinType("left_anti") === LeftAnti)
+  }
+
+  test("construct a Cross type") {
+    assert(JoinType("cross") === Cross)
+  }
+
+}