Diversified the test for multiple fields

Though this wasn't the problem, makes the tests more robust as more than
one type used in specialising the same generic type.

Author: thk123

jbmc/unit/java_bytecode/goto_program_generics/BWrapper.class

@@ -11,10 +11,10 @@ public void foo() {
 
   class MultipleGenericFields {
     Wrapper<IWrapper> field_input1;
-    Wrapper<IWrapper> field_input2;
+    Wrapper<BWrapper> field_input2;
     public void foo() {
         field_input1.field.i = 10;
-        field_input2.field.i = 20;
+        field_input2.field.b = true;
     }
   }
 

jbmc/unit/java_bytecode/goto_program_generics/GenericFields$MultipleGenericFields.class

@@ -6,6 +6,14 @@ public IWrapper(int ii) {
   }
 }
 
+// boolean wrapper
+class BWrapper {
+  public boolean b;
+  public BWrapper(boolean bb) {
+    b = bb;
+  }
+}
+
 // simple generic class
 class Wrapper<T> {
   public T field;

jbmc/unit/java_bytecode/goto_program_generics/GenericFields.java

@@ -136,13 +136,13 @@ SCENARIO(
             {},
             entry_point_code);
 
-        THEN("Object 'field_input1' has field 'field' of type IWrapper")
+        THEN("Object 'field_input2' has field 'field' of type BWrapper")
         {
           require_goto_statements::require_struct_component_assignment(
             field_input2_name,
             {},
             "field",
-            "java::IWrapper",
+            "java::BWrapper",
             {},
             entry_point_code);
         }