test: revert last commit it broke xapian build

Last commit caused the following error:

 /usr/bin/install -c -m 644 xapian/__init__.py
 xapian/__pycache__/__init__.cpython-310.pyc
 ./xapian/__pycache__/__init__. '/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/xapian'
/usr/bin/install: cannot stat './xapian/__pycache__/__init__.': No
 such file or directory

with the old code that errored out because of the missing sys import I
got the working:

 /usr/bin/install -c -m 644 xapian/__init__.py
 xapian/__pycache__/__init__.cpython-310.pyc
 xapian/__pycache__/__init__.cpython-310.opt-1.pyc
 '/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/xapian'

whatever.

Author: rouilj

.github/workflows/ci-test.yml

@@ -254,7 +254,7 @@ jobs:
               -e '/PYTHON3_SO=/s/"SO"/"EXT_SUFFIX"/g' \
               -e '/PYTHON3_CACHE_TAG=/s/imp;print(imp.get_tag())/sys;print(sys.implementation.cache_tag)/' \
               -e '/PYTHON3_CACHE_OPT1_EXT=/s/imp\.get_tag()/sys.implementation.cache_tag/g' \
-              -e '/PYTHON3_CACHE_OPT1_EXT=/s/imp\b/sys/g' \
+              -e '/PYTHON3_CACHE_OPT1_EXT=/s/imp\b/importlib/g' \
             configure; \
             diff -u configure.FCS configure || true; \
             ./configure --prefix=$VIRTUAL_ENV --with-python3 --disable-documentation; \