[Chapel Merge] Update error message when conflict due to re-expor

Branch: refs/heads/master
Revision: 4602ec0
Author: lydia-duncan
Log Message:

Merge pull request #16438 from lydia-duncan/tweakReexportError

Update error message when conflict due to re-exporting
[reviewed by @e-kayrakli]

It’s possible that the conflicting symbol that was re-exported had been
re-exported multiple times. In this case, looking at the re-export point could
be confusing for the user, since they’ll be told about it and the original
module where the symbol was defined. By adjusting the error message to say it
was the last point the symbol was re-exported from before the conflict, the user
is more likely to be open to the possibility that the symbol was re-exported
multiple times.

Resolves #16317

Updates the tests that tracked this error message for the new message.

Passed a full paratest with futures