[flang] Fix renames in module files

[flang] Fix renames in module files

When a module contains a use-association with rename, we have to be
careful to use the correct name (i.e. the local-name, not the use-name)
when writing out its `.mod` file.

When analyzing a `Name` in an expression, follow the use-association
for details, attributes, and constant values; but if we need to make a
`Designator` or `ProcedureDesignator`, use the local name.

Original-commit: flang-compiler/f18@8f07b803e141e34b3e512f8f02ef228186abe80f
Reviewed-on: https://github.com/flang-compiler/f18/pull/740
Tree-same-pre-rewrite: false