* mcs/ecore.cs (FieldExpr.EmitInstance): Catch cases of CS0120 that
slipped in because of variable names that are identical to a
builtin type's BCL equivalent ('string String;', 'int Int32;').
(PropertyExpr.EmitInstance): Likewise.
* errors/cs0120-6.cs, errors/cs0120-7.cs: New tests from #73394.
svn path=/trunk/mcs/; revision=41506
