Clean up semantics of invoking ResolveMemberAccess.

Clean up semantics of invoking ResolveMemberAccess.
* ecore.cs (SimpleName.DoSimpleNameResolve): If a MemberExpression
can have an instance, ensure that we pass in a non-TypeExpression
to ResolveMemberAccess.  Tighten up IdenticalNameAndTypeName checks.
(MemberExpr.DoSimpleNameResolve): Remove type_is_inferred
argument.  Update to changes and simplify.
(FieldExpr.Emitinstance): Remove CS0120 check.
(PropertyExpr.EmitInstance): Likewise.
* expression.cs (Argument.Resolve): Likewise.
(Invocation.DoResolve): Update to changes in semantics of
InstanceExpression.

svn path=/trunk/mcs/; revision=42432