[generator] Fix exception caused by incorrect nested type name. (#1267)

Context: #1266
Context: #1268

While the issue described in #1266 is definitely
an issue, that example was merely setting up the scenario needed to
expose another bug:

When a `Java.Lang.Object` or `Java.Interop.JavaObject` subclass
has a `public` or `internal` field whose type is a nested type:

	// C#
	namespace Com.Mypackage;

	[Register ("com/mypackage/FieldClass")]
	public class FieldClass : Java.Lang.Object {
	    public NestedFieldClass field;
	
	    public class NestedFieldClass : Java.Lang.Object {
	    }
	}

We correctly import the `Field.TypeName` as
`Com.Mypackage.FieldClass.NestedFieldClass`, however we also create
`Field.SetterParameter` with the "same" type, but we do not replace
the `/` nested type separator with a period, resulting in
`Com.Mypackage.FieldClass/NestedFieldClass`.

Later, when validating the `Field`, we successfully find
`Field.TypeName` in the symbol table, but fail to find
`Field.SetterParameter` as the symbol table expects a period nested
type separator.  (Note this only happens because `NestedFieldClass`
does not have a `[Register]` attribute, thus it gets added to the
symbol table with its managed name rather than its Java name.)

This causes `generator` to crash with:

	System.NotSupportedException: Unable to generate setter parameter list in managed type Com.Mypackage.FieldClass
	   at MonoDroid.Generation.Field.Validate(CodeGenerationOptions opt, GenericParameterDefinitionList type_params, CodeGeneratorContext context)
	   at MonoDroid.Generation.GenBase.OnValidate(CodeGenerationOptions opt, GenericParameterDefinitionList type_params, CodeGeneratorContext context)
	   at MonoDroid.Generation.ClassGen.OnValidate(CodeGenerationOptions opt, GenericParameterDefinitionList type_params, CodeGeneratorContext context)
	   at MonoDroid.Generation.GenBase.Validate(CodeGenerationOptions opt, GenericParameterDefinitionList type_params, CodeGeneratorContext context)

Fix this by applying the same `FullNameCorrected()` logic that is
applied to `Field.TypeName`.

tests/generator-Tests/Unit-Tests/ManagedTests.cs

@@ -41,6 +41,15 @@ public void UnknownTypes (object unknown) { }
 
 	[Register ("com/mypackage/service")]
 	public interface IService { }
+
+	[Register ("com/mypackage/FieldClass")]
+	public class FieldClass : Java.Lang.Object
+	{
+		public NestedFieldClass field;
+
+		public class NestedFieldClass : Java.Lang.Object { }
+	}
+
 }
 
 namespace GenericTestClasses
@@ -133,6 +142,21 @@ public void Class ()
 			Assert.IsNull (@class.DeprecatedComment);
 		}
 
+		[Test]
+		public void FieldWithNestedType ()
+		{
+			var @class = CecilApiImporter.CreateClass (module.GetType ("Com.Mypackage.FieldClass"), options);
+			var @class2 = CecilApiImporter.CreateClass (module.GetType ("Com.Mypackage.FieldClass/NestedFieldClass"), options);
+
+			options.SymbolTable.AddType (@class);
+			options.SymbolTable.AddType (@class2);
+
+			Assert.IsTrue (@class.Validate (options, new GenericParameterDefinitionList (), new CodeGeneratorContext ()), "@class.Validate failed!");
+
+			// Ensure the front slash is replaced with a period
+			Assert.AreEqual ("Com.Mypackage.FieldClass.NestedFieldClass", @class.Fields [0].TypeName);
+		}
+
 		[Test]
 		public void Method ()
 		{

tools/generator/Java.Interop.Tools.Generator.Importers/CecilApiImporter.cs

@@ -108,7 +108,8 @@ public static Field CreateField (FieldDefinition f)
 				Visibility = f.IsPublic ? "public" : f.IsFamilyOrAssembly ? "protected internal" : f.IsFamily ? "protected" : f.IsAssembly ? "internal" : "private"
 			};
 
-			field.SetterParameter = CreateParameter (f.FieldType.Resolve ()?.FullName ?? f.FieldType.FullName, null);
+			var field_parameter_type = f.FieldType.Resolve () ?? f.FieldType;
+			field.SetterParameter = CreateParameter (field_parameter_type.FullNameCorrected ().StripArity (), null);
 			field.SetterParameter.Name = "value";
 
 			return field;