1.0.39.2: Fix symbol-name-conflict resolution test from 1.0.39.1.

1.0.39.2: Fix symbol-name-conflict resolution test from 1.0.39.1.

  * Before signalling a name-conflict in IMPORT due to a symbol found
previously on the arglist, remove the earlier symbol from the list of
symbols to add to the package (one or the other will be shadowing-imported,
and there's no further check for name collision.