memory store clear is scoped to the path

Author: d-v-b

src/zarr/storage/memory.py

@@ -61,7 +61,9 @@ async def empty(self) -> bool:
 
     async def clear(self) -> None:
         # docstring inherited
-        self._store_dict.clear()
+        for k in tuple(self._store_dict.keys()):
+            if k.startswith(self.path):
+                del self._store_dict[k]
 
     def with_mode(self, mode: AccessModeLiteral) -> Self:
         # docstring inherited