bpo-30645: don't append to an inner loop path in imp.load_package() (GH-2268)

Bug didn't manifest itself when importing a module with source as .py files are always the first on the search path. The issue only showed up in bytecode-only packages where the calculated file path would be ``__init__.py/__init__.pyc``.

Patch by Alexandru Ardelean.
diff --git a/Misc/ACKS b/Misc/ACKS
index 4f98e98..eaff172 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -57,6 +57,7 @@
 Heidi Annexstad
 Ramchandra Apte
 Éric Araujo
+Alexandru Ardelean
 Alicia Arlen
 Jeffrey Armstrong
 Jason Asbahr