[SPARK-17007][SQL] Move test data files into a test-data folder

## What changes were proposed in this pull request?
This patch moves all the test data files in sql/core/src/test/resources to sql/core/src/test/resources/test-data, so we don't clutter the top level sql/core/src/test/resources. Also deleted sql/core/src/test/resources/old-repeated.parquet since it is no longer used.

The change will make it easier to spot sql-tests directory.

## How was this patch tested?
This is a test-only change.

Author: petermaxlee <petermaxlee@gmail.com>

Closes #14589 from petermaxlee/SPARK-17007.

sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java

@@ -327,23 +327,23 @@ public class JavaDataFrameSuite {
 
   @Test
   public void testGenericLoad() {
-    Dataset<Row> df1 = spark.read().format("text").load(getResource("text-suite.txt"));
+    Dataset<Row> df1 = spark.read().format("text").load(getResource("test-data/text-suite.txt"));
     Assert.assertEquals(4L, df1.count());
 
     Dataset<Row> df2 = spark.read().format("text").load(
-      getResource("text-suite.txt"),
-      getResource("text-suite2.txt"));
+      getResource("test-data/text-suite.txt"),
+      getResource("test-data/text-suite2.txt"));
     Assert.assertEquals(5L, df2.count());
   }
 
   @Test
   public void testTextLoad() {
-    Dataset<String> ds1 = spark.read().textFile(getResource("text-suite.txt"));
+    Dataset<String> ds1 = spark.read().textFile(getResource("test-data/text-suite.txt"));
     Assert.assertEquals(4L, ds1.count());
 
     Dataset<String> ds2 = spark.read().textFile(
-      getResource("text-suite.txt"),
-      getResource("text-suite2.txt"));
+      getResource("test-data/text-suite.txt"),
+      getResource("test-data/text-suite2.txt"));
     Assert.assertEquals(5L, ds2.count());
   }