nested_inheritance_interface testcase enhancement

Fixes unused variable reported by C# compiler and enhance test slightly

CHANGES.current

@@ -7,6 +7,10 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.0.1 (in progress)
 ===========================
 
+2019-07-09: IsaacPascual
+            [C#, Java] #1570 Fix name of generated C#/Java classes for %interface macros
+            in swiginterface.i when wrapping nested C++ classes.
+
 2019-06-24: wsfulton
             [Python, Ruby] #1538 Remove the UnknownExceptionHandler class in order to be
             C++17 compliant as it uses std::unexpected_handler which was removed in C++17.

Examples/test-suite/csharp/nested_inheritance_interface_runme.cs

@@ -16,6 +16,9 @@ public class nested_inheritance_interface_runme {
     return SortArrayToString(stypes.ToArray());
   }
 
+  private static void takeIA(IASwigInterface ia) {
+  }
+
   public static void Main() {
     Type[] BNInterfaces = typeof(B.N).GetInterfaces();
     string expectedInterfacesString = "IASwigInterface IDisposable";
@@ -28,5 +31,6 @@ public class nested_inheritance_interface_runme {
 
     // overloaded methods check
     B.N d = new B.N();
+    takeIA(d);
   }
 }

Examples/test-suite/java/nested_inheritance_interface_runme.java

@@ -12,6 +12,9 @@ public class nested_inheritance_interface_runme {
     }
   }
 
+  private static void takeIA(IASwigInterface ia) {
+  }
+
   public static void main(String argv[]) {
 	Class[] BNInterfaces = B.N.class.getInterfaces();
     String expectedInterfacesString = "[interface nested_inheritance_interface.IASwigInterface]";
@@ -24,5 +27,6 @@ public class nested_inheritance_interface_runme {
 
     // overloaded methods check
     B.N d = new B.N();
+    takeIA(d);
   }
 }