### What changes were proposed in this pull request?
Do not cast `NaN` to an `Integer`, `Long`, `Short` or `Byte`. This is because casting `NaN` to those types results in a `0` which erroneously replaces `0`s while only `NaN`s should be replaced.
### Why are the changes needed?
This Scala code snippet:
```
import scala.math;
println(Double.NaN.toLong)
```
returns `0` which is problematic as if you run the following Spark code, `0`s get replaced as well:
```
>>> df = spark.createDataFrame([(1.0, 0), (0.0, 3), (float('nan'), 0)], ("index", "value"))
>>> df.show()
+-----+-----+
|index|value|
+-----+-----+
| 1.0| 0|
| 0.0| 3|
| NaN| 0|
+-----+-----+
>>> df.replace(float('nan'), 2).show()
+-----+-----+
|index|value|
+-----+-----+
| 1.0| 2|
| 0.0| 3|
| 2.0| 2|
+-----+-----+
```
### Does this PR introduce any user-facing change?
Yes, after the PR, running the same above code snippet returns the correct expected results:
```
>>> df = spark.createDataFrame([(1.0, 0), (0.0, 3), (float('nan'), 0)], ("index", "value"))
>>> df.show()
+-----+-----+
|index|value|
+-----+-----+
| 1.0| 0|
| 0.0| 3|
| NaN| 0|
+-----+-----+
>>> df.replace(float('nan'), 2).show()
+-----+-----+
|index|value|
+-----+-----+
| 1.0| 0|
| 0.0| 3|
| 2.0| 0|
+-----+-----+
```
### How was this patch tested?
Added unit tests to verify replacing `NaN` only affects columns of type `Float` and `Double`
Closes#26738 from johnhany97/SPARK-30082.
Lead-authored-by: John Ayad <johnhany97@gmail.com>
Co-authored-by: John Ayad <jayad@palantir.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
8c2849a695