make LayoutInflater instances persistent per Context

Also implement LayoutInfater.cloneInContext() and support mutipe View
factories at once.

This is needed, so that androidx can repace all normal Views with
appcompat Views, which is needed for proper tint color support.

src/api-impl/android/app/Activity.java

@@ -407,7 +407,7 @@ public class Activity extends ContextThemeWrapper implements Window.Callback, La
 	}
 
 	public LayoutInflater getLayoutInflater() {
-		return new LayoutInflater(this);
+		return (LayoutInflater)getSystemService("layout_inflater");
 	}
 
 	public boolean isChangingConfigurations() {return false;}