Fix: pytest Wait 1 Sec

Simetimes our tests are so quick that they
finish below 1second. That does not work with
`UniqueStrings` in AMReX' `UtilCreateCleanDirectory`,
which can only do one name per second:
https://github.com/AMReX-Codes/amrex/blob/23.08/Src/Base/AMReX_Utility.cpp#L186-L199

If the target exist, the behavior of `std::rename` is
implementation dependent. We see crashes of this
on macOS.
https://en.cppreference.com/w/cpp/io/c/rename

tests/python/conftest.py

@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
 
+import time
+
 import pytest
 
 import amrex.space3d as amr
@@ -32,3 +34,8 @@ def amrex_init():
     )
     yield
     amr.finalize()
+
+    # sleep 1s because AMReX diagnostics cleanup can only do one rename
+    # per second
+    # https://github.com/AMReX-Codes/amrex/blob/23.08/Src/Base/AMReX_Utility.cpp#L186-L199
+    time.sleep(1)