[SPARK-22326][SQL] Remove unnecessary hashCode and equals methods

## What changes were proposed in this pull request?

Plan equality should be computed by `canonicalized`, so we can remove unnecessary `hashCode` and `equals` methods.

## How was this patch tested?

Existing tests.

Author: Zhenhua Wang <wangzhenhua@huawei.com>

Closes #19539 from wzhfy/remove_equals.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/catalog/interface.scala

@@ -22,8 +22,6 @@ import java.util.Date
 
 import scala.collection.mutable
 
-import com.google.common.base.Objects
-
 import org.apache.spark.sql.AnalysisException
 import org.apache.spark.sql.catalyst.{FunctionIdentifier, InternalRow, TableIdentifier}
 import org.apache.spark.sql.catalyst.analysis.MultiInstanceRelation
@@ -440,15 +438,6 @@ case class HiveTableRelation(
 
   def isPartitioned: Boolean = partitionCols.nonEmpty
 
-  override def equals(relation: Any): Boolean = relation match {
-    case other: HiveTableRelation => tableMeta == other.tableMeta && output == other.output
-    case _ => false
-  }
-
-  override def hashCode(): Int = {
-    Objects.hashCode(tableMeta.identifier, output)
-  }
-
   override lazy val canonicalized: HiveTableRelation = copy(
     tableMeta = tableMeta.copy(
       storage = CatalogStorageFormat.empty,

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/LogicalRelation.scala

@@ -34,17 +34,6 @@ case class LogicalRelation(
     override val isStreaming: Boolean)
   extends LeafNode with MultiInstanceRelation {
 
-  // Logical Relations are distinct if they have different output for the sake of transformations.
-  override def equals(other: Any): Boolean = other match {
-    case l @ LogicalRelation(otherRelation, _, _, isStreaming) =>
-      relation == otherRelation && output == l.output && isStreaming == l.isStreaming
-    case _ => false
-  }
-
-  override def hashCode: Int = {
-    com.google.common.base.Objects.hashCode(relation, output)
-  }
-
   // Only care about relation when canonicalizing.
   override lazy val canonicalized: LogicalPlan = copy(
     output = output.map(QueryPlan.normalizeExprId(_, output)),