test-case: add missing pipeline count acquisition logic

[aiChaoSONG]

The commit 84f5895 wrongly remove the code logic to
acquire pipeline count from multi-pipeline-playback/
capture test cases. This leads to the 'max_count' used
in these scripts being empty, as no pipeline is actually
tested, the test cases will always pass.

This patch adds the pipeline count acquisition logic back.

[marc-hb]

Since #373 was merged I see that multiple-pipeline tests have an empty trace like this:

2020-09-15 00:00:31 UTC [REMOTE_INFO] nlines=1 /home/ubuntu/sof-test/logs/multiple-pipeline-capture/2020-09-15-00:00:20-8571/slogger.txt

This will become a FAIL once #297 is fully implemented.

[marc-hb]

This looks like a partial revert of 84f5895 / PR #281. If it is then it should be mentioned in the commit message.

[aiChaoSONG]

@marc-hb thanks, will update commit message to mention 84f5895

[marc-hb]

Since #373 was merged I see that multiple-pipeline tests have an empty trace like this:

Forgot to mention it's intermittently empty on my Up2 board. This fix does not look like a fix for a non-deterministic issue...

@aiChaoSONG what's your logger experience when running the multipipeline tests? Before and after this PR?

UPDATE after a bit more testing: not intermittently empty: empty the second time I run ./test-case/multiple-pipeline-playback.sh. It's probably a different issue.

[aiChaoSONG]

@marc-hb Before this PR, the test case always PASS, even the topology not loaded(should fail), and the terminal message like this:

2020-09-18 05:13:38 UTC [INFO] Starting /usr/bin/sof-logger -t -l /etc/sof/sof-cml.ldc -o /home/ubuntu/Downloads/sof-test/logs/multiple-pipeline-playback/2020-09-18-13:13:38-30729/slogger.txt
2020-09-18 05:13:38 UTC [INFO] ===== Testing: (Loop: 1/1) =====
2020-09-18 05:13:38 UTC [INFO] pipeline start sleep 0.5s for device wakeup
2020-09-18 05:13:43 UTC [INFO] checking pipeline status
2020-09-18 05:13:43 UTC [INFO] preparing sleep 5
2020-09-18 05:13:48 UTC [INFO] checking pipeline again
2020-09-18 05:13:49 UTC [INFO] nlines=1 /home/ubuntu/Downloads/sof-test/logs/multiple-pipeline-playback/2020-09-18-13:13:38-30729/slogger.txt
2020-09-18 05:13:50 UTC [INFO] Test Result: PASS!

After this PR, if topology loaded, terminal message looks like this:
terminal_msg.txt
if topology load failed, terminal message looks like this:
terminal_msg.txt

In fact, before this PR, no pipeline is checked, that's why it always pass.

[keyonjie]

Thanks for spotting it.

[aiChaoSONG]

merge for tgl release

[fredoh9]

LGTM, thanks for the fix