[SPARK-17008][SPARK-17009][SQL] Normalization and isolation in SQLQueryTestSuite.

## What changes were proposed in this pull request?
This patch enhances SQLQueryTestSuite in two ways:

1. SPARK-17009: Use a new SparkSession for each test case to provide stronger isolation (e.g. config changes in one test case does not impact another). That said, we do not currently isolate catalog changes.
2. SPARK-17008: Normalize query output using sorting, inspired by HiveComparisonTest.

I also ported a few new test cases over from SQLQuerySuite.

## How was this patch tested?
This is a test harness update.

Author: petermaxlee <petermaxlee@gmail.com>

Closes #14590 from petermaxlee/SPARK-17008.

1 files changed, 64 insertions, 0 deletions

diff --git a/sql/core/src/test/resources/sql-tests/results/natural-join.sql.out b/sql/core/src/test/resources/sql-tests/results/natural-join.sql.out
new file mode 100644
index 0000000000..d4954dabea
--- /dev/null
+++ b/sql/core/src/test/resources/sql-tests/results/natural-join.sql.out
@@ -0,0 +1,64 @@
+-- Automatically generated by org.apache.spark.sql.SQLQueryTestSuite
+-- Number of queries: 6
+
+
+-- !query 0
+create temporary view nt1 as select * from values
+  ("one", 1),
+  ("two", 2),
+  ("three", 3)
+  as nt1(k, v1)
+-- !query 0 schema
+struct<>
+-- !query 0 output
+
+
+
+-- !query 1
+create temporary view nt2 as select * from values
+  ("one", 1),
+  ("two", 22),
+  ("one", 5)
+  as nt2(k, v2)
+-- !query 1 schema
+struct<>
+-- !query 1 output
+
+
+
+-- !query 2
+SELECT * FROM nt1 natural join nt2 where k = "one"
+-- !query 2 schema
+struct<k:string,v1:int,v2:int>
+-- !query 2 output
+one	1	1
+one	1	5
+
+
+-- !query 3
+SELECT * FROM nt1 natural left join nt2 order by v1, v2
+-- !query 3 schema
+struct<k:string,v1:int,v2:int>
+-- !query 3 output
+one	1	1
+one	1	5
+two	2	22
+three	3	NULL
+
+
+-- !query 4
+SELECT * FROM nt1 natural right join nt2 order by v1, v2
+-- !query 4 schema
+struct<k:string,v1:int,v2:int>
+-- !query 4 output
+one	1	1
+one	1	5
+two	2	22
+
+
+-- !query 5
+SELECT count(*) FROM nt1 natural full outer join nt2
+-- !query 5 schema
+struct<count(1):bigint>
+-- !query 5 output
+4