tests: remove broken coverage support

coverage needs to be started before importing the modules, so it can
not be started so late in runUnitTest, it has to be started before
importing any Products/ERP5* code, ie. in slapos wrapper script.

See https://coverage.readthedocs.io/en/6.5.0/faq.html#q-why-do-the-bodies-of-functions-show-as-executed-but-the-def-lines-do-not
for more details about the rationale

product/ERP5Type/tests/runUnitTest.py

@@ -12,10 +12,7 @@ import errno
 import random
 import transaction
 from glob import glob
-try:
-  from coverage import coverage
-except ImportError:
-  coverage = None
+
 
 WIN = os.name == 'nt'
 
@@ -27,8 +24,6 @@ Options:
   -v, --verbose              produce verbose output
   -h, --help                 this help screen
   -p, --profile              print profiling results at the end
-  --coverage=STRING          Use the given path as a coverage config file and
-                             thus enable code coverateg report
   --portal_id=STRING         force id of the portal. Useful when using
                              --data_fs_path to run tests on an existing
                              Data.fs
@@ -638,11 +633,6 @@ def runUnitTestList(test_list, verbosity=1, debug=0, run_only=None):
     signal.signal(signal.SIGINT, shutdown)
   signal.signal(signal.SIGHUP, shutdown)
 
-  coverage_config = os.environ.get('coverage', None)
-  if coverage_config:
-    coverage_process = coverage(config_file=coverage_config)
-    coverage_process.start()
-
   try:
     save = int(os.environ.get('erp5_save_data_fs', 0))
     load = int(os.environ.get('erp5_load_data_fs', 0))
@@ -717,11 +707,6 @@ def runUnitTestList(test_list, verbosity=1, debug=0, run_only=None):
       # disconnected from it.
       wcfs_server.stop()
 
-  if coverage_config:
-    coverage_process.stop()
-    coverage_process.save()
-    coverage_process.html_report()
-
   if save and save_mysql:
     save_mysql(verbosity)
 
@@ -747,7 +732,7 @@ def main(argument_list=None):
   sys.argv.extend(old_argv[1:])
   try:
     opts, args = getopt.getopt(sys.argv[1:],
-        "hpvD", ["help", "verbose", "profile", "coverage=", "portal_id=",
+        "hpvD", ["help", "verbose", "profile", "portal_id=",
         "data_fs_path=",
         "bt5_path=",
         "firefox_bin=",
@@ -810,11 +795,6 @@ def main(argument_list=None):
     elif opt == '-D':
       debug = 1
       os.environ["erp5_debug_mode"] = str(debug)
-    elif opt == "--coverage":
-      if coverage:
-        os.environ['coverage'] = arg
-      else:
-        _print("WARNING Coverage module not found")
     elif opt in ("-p", "--profile"):
       os.environ['PROFILE_TESTS'] = "1"
       # profiling of setup and teardown is disabled by default, just set