[SPARK-51881][SQL] Make AvroOptions comparable

### What changes were proposed in this pull request?

Make AvroOptions comparable. Hadoop `Configuration` doesn't have equals, but it's enough to compare `parameters`.

### Why are the changes needed?

To properly compare single-pass/fixed-point Analyzer logical plans.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Existing tests.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #50683 from vladimirg-db/vladimir-golubev_data/make-avro-options-comparable.

Authored-by: Vladimir Golubev <vladimir.golubev@databricks.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>

Author: vladimirg-db

sql/core/src/main/scala/org/apache/spark/sql/avro/AvroOptions.scala

@@ -18,6 +18,7 @@
 package org.apache.spark.sql.avro
 
 import java.net.URI
+import java.util.HashMap
 
 import org.apache.avro.Schema
 import org.apache.hadoop.conf.Configuration
@@ -146,6 +147,37 @@ private[sql] class AvroOptions(
       RECURSIVE_FIELD_MAX_DEPTH,
       s"Should not be greater than $RECURSIVE_FIELD_MAX_DEPTH_LIMIT.")
   }
+
+  /**
+   * [[hadoop.conf.Configuration]] is not comparable so we turn it into a map for [[equals]] and
+   * [[hashCode]].
+   */
+  @transient private lazy val comparableConf = {
+    val iter = conf.iterator()
+    val result = new HashMap[String, String]
+    while (iter.hasNext()) {
+      val entry = iter.next()
+      result.put(entry.getKey(), entry.getValue())
+    }
+    result
+  }
+
+  override def equals(other: Any): Boolean = {
+    other match {
+      case that: AvroOptions =>
+        this.parameters == that.parameters &&
+        this.comparableConf == that.comparableConf
+      case _ => false
+    }
+  }
+
+  override def hashCode(): Int = {
+    val prime = 31
+    var result = 1
+    result = prime * result + parameters.hashCode
+    result = prime * result + comparableConf.hashCode
+    result
+  }
 }
 
 private[sql] object AvroOptions extends DataSourceOptions {