[SPARK-56353][BUILD][TESTS][FOLLOWUP] Fix resource loading to work when resources are inside JARs

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

This PR fixes `FileSystemNotFoundException` in `TestSpark21101Jar`, `TestUDTFJar`, and `TestHiveUdfsJar` when running tests with Maven.

These files used `Paths.get(url.toURI)` to read Java source files from classpath resources. This works with SBT where resources are extracted to `target/test-classes/` as regular files, but fails with Maven where resources may be inside JAR files, producing a `jar:file:...!/path` URI that `Paths.get()` cannot handle without a ZipFileSystem.

The fix replaces `Files.readAllBytes(Paths.get(url.toURI))` with `url.openStream().readAllBytes()`, which works regardless of whether the resource is a regular file or inside a JAR.

### Why are the changes needed?

CI runs with Maven and hits `FileSystemNotFoundException` when initializing `TestUDTFJar`, causing `CliSuite` and `HiveThriftBinaryServerSuite` to fail:

```
Cause: java.lang.ExceptionInInitializerError:
  Exception java.nio.file.FileSystemNotFoundException
  at jdk.zipfs/jdk.nio.zipfs.ZipFileSystemProvider.getFileSystem(ZipFileSystemProvider.java:156)
  at java.base/java.nio.file.Paths.get(Paths.java:98)
  at org.apache.spark.sql.hive.test.TestUDTFJar$.loadResource(TestUDTFJar.scala:37)
```

Reported in #55272 (comment)

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?
Verified with Maven (the environment where the failure occurs):
- CliSuite: 44/44 passed
- HiveThriftBinaryServerSuite: 30/30 passed

### Was this patch authored or co-authored using generative AI tooling?
Kiro CLI / Opus 4.6

Closes #55299 from sarutak/fix-resource-loading.

Authored-by: Kousuke Saruta <sarutak@amazon.co.jp>
Signed-off-by: Cheng Pan <chengpan@apache.org>

Author: sarutak

sql/hive/src/test/scala/org/apache/spark/sql/hive/test/TestHiveUdfsJar.scala

@@ -20,7 +20,6 @@ package org.apache.spark.sql.hive.test
 import java.io.File
 import java.lang.management.ManagementFactory
 import java.nio.charset.StandardCharsets
-import java.nio.file.{Files, Paths}
 
 import org.apache.spark.util.{SparkTestUtils, Utils}
 
@@ -64,6 +63,8 @@ object TestHiveUdfsJar {
   private def readResource(name: String): String = {
     val url = Thread.currentThread().getContextClassLoader.getResource(name)
     assert(url != null, s"Resource not found: $name")
-    new String(Files.readAllBytes(Paths.get(url.toURI)), StandardCharsets.UTF_8)
+    Utils.tryWithResource(url.openStream()) { is =>
+      new String(is.readAllBytes(), StandardCharsets.UTF_8)
+    }
   }
 }

sql/hive/src/test/scala/org/apache/spark/sql/hive/test/TestSpark21101Jar.scala

@@ -20,7 +20,6 @@ package org.apache.spark.sql.hive.test
 import java.io.File
 import java.lang.management.ManagementFactory
 import java.nio.charset.StandardCharsets
-import java.nio.file.{Files, Paths}
 
 import org.apache.spark.util.{SparkTestUtils, Utils}
 
@@ -52,6 +51,8 @@ object TestSpark21101Jar {
   private def readResource(name: String): String = {
     val url = Thread.currentThread().getContextClassLoader.getResource(name)
     assert(url != null, s"Resource not found: $name")
-    new String(Files.readAllBytes(Paths.get(url.toURI)), StandardCharsets.UTF_8)
+    Utils.tryWithResource(url.openStream()) { is =>
+      new String(is.readAllBytes(), StandardCharsets.UTF_8)
+    }
   }
 }

sql/hive/src/test/scala/org/apache/spark/sql/hive/test/TestUDTFJar.scala

@@ -20,7 +20,6 @@ package org.apache.spark.sql.hive.test
 import java.io.File
 import java.lang.management.ManagementFactory
 import java.nio.charset.StandardCharsets
-import java.nio.file.{Files, Paths}
 
 import org.apache.spark.TestUtils
 import org.apache.spark.util.Utils
@@ -34,7 +33,9 @@ object TestUDTFJar {
   private def loadResource(name: String): String = {
     val url = Thread.currentThread().getContextClassLoader.getResource(name)
     assert(url != null, s"Resource not found: $name")
-    new String(Files.readAllBytes(Paths.get(url.toURI)), StandardCharsets.UTF_8)
+    Utils.tryWithResource(url.openStream()) { is =>
+      new String(is.readAllBytes(), StandardCharsets.UTF_8)
+    }
   }
 
   private val source = Map(