Fix default argument in TableRow constructor

Add type parameter to default constructor angument in scalafx.scene.control.TableRow constructor, which otherwise resolved to jfxsc.TableRow[Nothing], causing type error:
```
scala> new scalafx.scene.control.TableRow[String]
<console>:8: error: type mismatch;
 found   : javafx.scene.control.TableRow[Nothing]
 required: javafx.scene.control.TableRow[String]
Note: Nothing <: String, but Java-defined class TableRow is invariant in type T.
You may wish to investigate a wildcard type such as `_ <: String`. (SLS 3.2.10)
Error occurred in an application involving default arguments.
              new scalafx.scene.control.TableRow[String]
              ^
```