[SPARK-2615] [SQL] Add Equal Sign "==" Support for HiveQl

Currently, the "==" in HiveQL expression will cause exception thrown, this patch will fix it.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #1522 from chenghao-intel/equal and squashes the following commits:

f62a0ff [Cheng Hao] Add == Support for HiveQl

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveQl.scala

@@ -932,6 +932,7 @@ private[hive] object HiveQl {
 
     /* Comparisons */
     case Token("=", left :: right:: Nil) => EqualTo(nodeToExpr(left), nodeToExpr(right))
+    case Token("==", left :: right:: Nil) => EqualTo(nodeToExpr(left), nodeToExpr(right))
     case Token("!=", left :: right:: Nil) => Not(EqualTo(nodeToExpr(left), nodeToExpr(right)))
     case Token("<>", left :: right:: Nil) => Not(EqualTo(nodeToExpr(left), nodeToExpr(right)))
     case Token(">", left :: right:: Nil) => GreaterThan(nodeToExpr(left), nodeToExpr(right))

sql/hive/src/test/resources/golden/correlationoptimizer13-2-777edd9d575f3480ca6cebe4be57b1f6

+0

sql/hive/src/test/resources/golden/correlationoptimizer9-1-b1e2ade89ae898650f0be4f796d8947b

+0

sql/hive/src/test/resources/golden/correlationoptimizer9-11-bc2ae88b17ac2bdbd288e07194a40168

+103	val_103	103	val_103	4	4
+104	val_104	104	val_104	4	4
+105	val_105	105	val_105	1	1
+111	val_111	111	val_111	1	1
+113	val_113	113	val_113	4	4
+114	val_114	114	val_114	1	1
+116	val_116	116	val_116	1	1
+118	val_118	118	val_118	4	4
+119	val_119	119	val_119	9	9

sql/hive/src/test/resources/golden/correlationoptimizer9-12-777edd9d575f3480ca6cebe4be57b1f6

+0

sql/hive/src/test/resources/golden/correlationoptimizer9-14-bc2ae88b17ac2bdbd288e07194a40168

+103	val_103	103	val_103	4	4
+104	val_104	104	val_104	4	4
+105	val_105	105	val_105	1	1
+111	val_111	111	val_111	1	1
+113	val_113	113	val_113	4	4
+114	val_114	114	val_114	1	1
+116	val_116	116	val_116	1	1
+118	val_118	118	val_118	4	4
+119	val_119	119	val_119	9	9

sql/hive/src/test/resources/golden/correlationoptimizer9-3-b9d963d24994c47c3776dda6f7d3881f

+0

sql/hive/src/test/resources/golden/correlationoptimizer9-5-b4e378104bb5ab8d8ba5f905aa1ff450

+103	103	4	4
+104	104	4	4
+105	105	1	1
+111	111	1	1
+113	113	4	4
+114	114	1	1
+116	116	1	1
+118	118	4	4
+119	119	9	9

sql/hive/src/test/resources/golden/correlationoptimizer9-6-777edd9d575f3480ca6cebe4be57b1f6

+0

sql/hive/src/test/resources/golden/correlationoptimizer9-8-b4e378104bb5ab8d8ba5f905aa1ff450

+103	103	4	4
+104	104	4	4
+105	105	1	1
+111	111	1	1
+113	113	4	4
+114	114	1	1
+116	116	1	1
+118	118	4	4
+119	119	9	9

sql/hive/src/test/resources/golden/correlationoptimizer9-9-b9d963d24994c47c3776dda6f7d3881f

+0