C# parser: preserve order of constraints
Fixed issues with control flow analysis on incomplete AST.
Insert after last using instead of inserting before namespace declaration.

This affects the placement of whitespace.
Un-ignore some tests that were fixed
Update NRefactory version number to 5.3.0
Fix MemberType.DoMatch() - pattern matching was ignoring the type arguments.
Use SyntaxTree.MemberRole for assembly attributes.
Indexer declaration: make "this" a token instead of an identifier
Fix pattern matching for ComposedType.BaseType.
Add consistency check that mutates the AST and checks if pattern matching finds the difference.
Update NRefactory to 5.3.0-5-g33c882d