[Java.Interop.Tools.JavaTypeSystem] ctors w/ generic type parameters (#919)

While [testing][0] the new JavaTypeSystem (f658ab2) on [AndroidX][1],
the api-diff was reporting various constructors had been removed:

	## Xamarin.Android.Glide.dll
	#### Type Changed: Bumptech.Glide.Registry.NoModelLoaderAvailableException
	
	Removed constructor:
	
	```csharp
	public Registry.NoModelLoaderAvailableException (Java.Lang.Object model, System.Collections.IList matchingButNotHandlingModelLoaders);
	```
	
	Investigating let to realizing Java constructors can have generic type parameters:
	
	```java
	  public static class NoModelLoaderAvailableException extends MissingComponentException {
	  
	    public <M> NoModelLoaderAvailableException(
	        @nonnull M model, @nonnull List<ModelLoader<M, ?>> matchingButNotHandlingModelLoaders) {
	      super(
	          "Found ModelLoaders for model class: "
	              + matchingButNotHandlingModelLoaders
	              + ", but none that handle this specific model instance: "
	              + model);
	    }
	```

[(source)][2]

`class-parse` correctly emits these constructors with generic types:

	```xml
	<constructor
	  deprecated="not deprecated"
	  final="false"
	  name="Registry.NoModelLoaderAvailableException"
	  static="false"
	  visibility="public"
	  bridge="false"
	  synthetic="false"
	  jni-signature="(Ljava/lang/Object;Ljava/util/List;)V">
	  <typeParameters>
	    <typeParameter
	      name="M"
	      jni-classBound="Ljava/lang/Object;"
	      classBound="java.lang.Object"
	      interfaceBounds=""
	      jni-interfaceBounds="" />
	  </typeParameters>
	  <parameter
	    name="model"
	    type="M"
	    jni-type="TM;"
	    not-null="true" />
	  <parameter
	    name="matchingButNotHandlingModelLoaders"
	    type="java.util.List&lt;com.bumptech.glide.load.model.ModelLoader&lt;M, ?&gt;&gt;"
	    jni-type="Ljava/util/List&lt;Lcom/bumptech/glide/load/model/ModelLoader&lt;TM;*&gt;;&gt;;"
	    not-null="true" />
	</constructor>
	```

We need to import this information in JavaTypeSystem so that the type
parameters can be resolved.  Without them, the constructor is omitted
because the type `M` cannot be resolved:

	The constructor 'Constructor: com.bumptech.glide.Registry.NoModelLoaderAvailableException.Registry.NoModelLoaderAvailableException'
	was removed because the Java parameter type 'M' could not be found.

Tested against AndroidX and this change restores the constructors.

[0]: dotnet/android-libraries#414
[1]: https://github.com/xamarin/AndroidX
[2]: https://github.com/bumptech/glide/blob/master/library/src/main/java/com/bumptech/glide/Registry.java

Author: jpobst

src/Java.Interop.Tools.JavaTypeSystem/Adapters/JavaXmlApiImporter.cs

@@ -229,6 +229,10 @@ public static JavaConstructorModel ParseConstructor (JavaTypeModel type, XElemen
 				isBridge: element.XGetAttributeAsBool ("bridge")
 			);
 
+			// Yes, constructors in Java can have generic type parameters ¯\_(ツ)_/¯
+			if (element.Element ("typeParameters") is XElement tp)
+				ParseTypeParameters (method.TypeParameters, tp);
+
 			foreach (var child in element.Elements ("exception"))
 				method.Exceptions.Add (ParseException (child));