[Chapel Merge] Switch more form_Map to sorted iteration

Branch: refs/heads/master
Revision: ff9b3a7
Author: vasslitvinov
Log Message:

Merge pull request #17424 from vasslitvinov/sorted-form_Map

Switch more form_Map to sorted iteration

This propagates the work in #17412 into interfaceResolution.cpp

While there, switch the functionality added in #17412 from std::pair
to a meaningful struct and simplify its uses.

r: @mppf

Modified Files:
M compiler/AST/symbol.cpp

M compiler/include/symbol.h
M compiler/passes/createTaskFunctions.cpp
M compiler/passes/flattenFunctions.cpp
M compiler/resolution/cleanups.cpp
M compiler/resolution/functionResolution.cpp
M compiler/resolution/generics.cpp
M compiler/resolution/interfaceResolution.cpp

Compare: https://github.com/chapel-lang/chapel/compare/62d7e66c8439...ff9b3a76ceac