Fix #79148.
* anonymous.cs
(ScopeInfo.ctor): Use `Modifiers.PUBLIC' if we're a nested
CompilerGeneratedClass.
(ScopeInfo.EmitScopeInstance): Make this protected.
(CapturedVariable.EmitInstance): Use `Ldarg_0' if
`ec.CurrentAnonymousMethod.Scope == Scope'.
* statement.cs (Block.ScopeInfo): Make this a property.
svn path=/trunk/mcs/; revision=75127