[Concepts] Fix parsing of scope specifier in compound-requirements, add more tests for scope specifiers in type-constraints
The code for parsing of type-constraints in compound-requirements was not adapted for the new TryAnnotateTypeConstraint which
caused compound-requirements with scope specifiers to ignore them.
Also add regression tests for scope specifiers in type-constraints in more contexts.
(cherry picked from commit 5043962dd3150c6ac72b75174b9460a510d1b5c3)