pySim-shell_test/utils: delete log files in general
When we get rid of temporary files, we delete those using a wildcard, but for the logs from pySim-shell we explicitly memorize the name of the pySim-shell logfile and delete it later by this explicit name. This is not necessary, let's just delete all log files present using a wildcard.
When pySim-shell is called by a testcase, a logfile is createted. The logfile filename contains the testcase name. However, a testcase may run pySim-shell multiple times. In this case we overwrite the log from previous run. Let's use a counter to generate unique file names for each run, so that we won't lose logs from previous runs.
When we configure the tests to display file content, we only display files that we compare, let's also display log file contents from pySim-shell. This will be useful in situations where we only have log output from the tests, but no access to the file system of the test host.