[Chapel Merge] Move resolveSpecifiedReturnType()

Branch: refs/heads/master
Revision: fefaa9c
Author: vasslitvinov
Log Message:

Merge pull request #17484 from vasslitvinov/resolveSpecifiedReturnType

Move resolveSpecifiedReturnType()

Execute resolveSpecifiedReturnType() for concrete functions only, for clarity.

It used to be executed for generic functions as well,
however that seems unnecessary and raises the question "why".

r: @mppf

Modified Files:
M compiler/resolution/ResolutionCandidate.cpp

Compare: https://github.com/chapel-lang/chapel/compare/5a64b3b7cdbb...fefaa9c84122