Hide overridden JLO machinery from editor

[jpobst]

In dotnet/android#4582 we hid "internal" methods like Java.Lang.Object.ThresholdClass from the editor and debugger using [DebuggerBrowsable (DebuggerBrowsableState.Never)] and [EditorBrowsable (EditorBrowsableState.Never)]. However our bindings override some of these methods/properties and need to also apply these attributes or else they still show up in IDEs.