Remove incorrect assertions in scala tests

We ran unit tests of spark on aarch64 server,
then found the values of floatToRawIntBits(0.0f / 0.0f)
and floatToRawIntBits(Float.NaN) on aarch64 are same,
after discuss with jdk-dev and scala community, we believe
the value should depend on the architecture.

This removes the incorrect assertions to make sure
the tests fit all architectures.

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),