[SPARK-28433][SQL][TEST] Remove hardware-dependent 0.0/0.0 and NaN comparison assertions

## What changes were proposed in this pull request?

This PR removes a few hardware-dependent assertions which can cause a failure in `aarch64`.

**x86_64**
```
rootdonotdel-openlab-allinone-l00242678:/home/ubuntu# uname -a
Linux donotdel-openlab-allinone-l00242678 4.4.0-154-generic apache-spark-on-k8s#181-Ubuntu SMP Tue Jun 25 05:29:03 UTC
2019 x86_64 x86_64 x86_64 GNU/Linux

scala> import java.lang.Float.floatToRawIntBits
import java.lang.Float.floatToRawIntBits
scala> floatToRawIntBits(0.0f/0.0f)
res0: Int = -4194304
scala> floatToRawIntBits(Float.NaN)
res1: Int = 2143289344
```

**aarch64**
```
[rootarm-huangtianhua spark]# uname -a
Linux arm-huangtianhua 4.14.0-49.el7a.aarch64 #1 SMP Tue Apr 10 17:22:26 UTC 2018 aarch64 aarch64 aarch64 GNU/Linux

scala> import java.lang.Float.floatToRawIntBits
import java.lang.Float.floatToRawIntBits
scala> floatToRawIntBits(0.0f/0.0f)
res1: Int = 2143289344
scala> floatToRawIntBits(Float.NaN)
res2: Int = 2143289344
```

## How was this patch tested?

Pass the Jenkins (This removes the test coverage).

Closes apache#25186 from huangtianhua/special-test-case-for-aarch64.

Authored-by: huangtianhua <huangtianhua@huawei.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

Author: huangtianhua

sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala

@@ -725,13 +725,6 @@ class DataFrameAggregateSuite extends QueryTest with SharedSQLContext {
   }
 
   test("SPARK-26021: NaN and -0.0 in grouping expressions") {
-    import java.lang.Float.floatToRawIntBits
-    import java.lang.Double.doubleToRawLongBits
-
-    // 0.0/0.0 and NaN are different values.
-    assert(floatToRawIntBits(0.0f/0.0f) != floatToRawIntBits(Float.NaN))
-    assert(doubleToRawLongBits(0.0/0.0) != doubleToRawLongBits(Double.NaN))
-
     checkAnswer(
       Seq(0.0f, -0.0f, 0.0f/0.0f, Float.NaN).toDF("f").groupBy("f").count(),
       Row(0.0f, 2) :: Row(Float.NaN, 2) :: Nil)

sql/core/src/test/scala/org/apache/spark/sql/DataFrameWindowFunctionsSuite.scala

@@ -697,13 +697,6 @@ class DataFrameWindowFunctionsSuite extends QueryTest with SharedSQLContext {
   }
 
   test("NaN and -0.0 in window partition keys") {
-    import java.lang.Float.floatToRawIntBits
-    import java.lang.Double.doubleToRawLongBits
-
-    // 0.0/0.0 and NaN are different values.
-    assert(floatToRawIntBits(0.0f/0.0f) != floatToRawIntBits(Float.NaN))
-    assert(doubleToRawLongBits(0.0/0.0) != doubleToRawLongBits(Double.NaN))
-
     val df = Seq(
       (Float.NaN, Double.NaN),
       (0.0f/0.0f, 0.0/0.0),