ngcc's reflection host needs to be able to determine all members of a
class, which it does by using the `ts.Symbol` from TypeScript's
TypeChecker. Such Symbol however may represent multiple class members
in the case of accessors; an equally named getter/setter accessor pair
is combined into a single `ts.Symbol`.
This commit introduces logic to recognize such accessors in order for
both the getter and setter to be considered as class member, similar to
ngtsc's behavior when operating on original TypeScript code.
One difference wrt the TypeScript host is that ngcc cannot see to which
accessor originally had any decorators applied to them, as decorators
are applied to the property descriptor in general, not a specific accessor.
If an accessor has both a setter and getter, any decorators are only
attached to the setter member.
PR Close#28357