tests: runtime: in_ne: add test for in_node_exporter_metrics

[nokute78]

This patch is to add test code for in_node_exporter_metrics and pseudo procfs and sysfs files.

---

Enter [N/A] in the box, if an item is not applicable to your change.

Testing
Before we can approve your change; please submit the following in a comment:

• [N/A] Example configuration file for the change
• Debug log output from testing the change

• Attached Valgrind output that shows no leaks or memory corruption was found

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• [N/A] Run local packaging test showing all targets (including any new ones) build.
• [N/A] Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• [N/A] Documentation required for this feature

Backporting

• [N/A] Backport to latest stable release.

Debug/Valgrind output

$ valgrind --leak-check=full bin/flb-rt-in_node_exporter_metrics 
==125756== Memcheck, a memory error detector
==125756== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==125756== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==125756== Command: bin/flb-rt-in_node_exporter_metrics
==125756== 
Test cpu...                                     [ OK ]
Test meminfo...                                 [ OK ]
Test diskstats...                               [ OK ]
Test uname...                                   [ OK ]
Test stat...                                    [ OK ]
Test time...                                    [ OK ]
Test loadavg...                                 [ OK ]
Test vmstat...                                  [ OK ]
Test netdev...                                  [ OK ]
Test filefd...                                  [ OK ]
SUCCESS: All unit tests have passed.
==125756== 
==125756== HEAP SUMMARY:
==125756==     in use at exit: 0 bytes in 0 blocks
==125756==   total heap usage: 28,680 allocs, 28,680 frees, 12,661,824 bytes allocated
==125756== 
==125756== All heap blocks were freed -- no leaks are possible
==125756== 
==125756== For lists of detected and suppressed errors, rerun with: -s
==125756== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[nokute78]

Windows CI failed, but it is not related this PR.
https://ci.appveyor.com/project/fluent/fluent-bit-2e87g/builds/48279470/job/hjgo14ys7wqjwjb5#L4226

31/42 Test #31: flb-it-log .......................***Failed   20.23 sec
Test cache_basic_timeout...                     
------------------------
[ FAILED ]
  log.c:16: Check (*interval >= timeout - 1) && *interval <= timeout... failed
    interval error. got=3 expect=4-5
  log.c:92: Check ret == 0... failed
    update_and_check_interval for TEST_RECORD_01 failed. i=9
  log.c:16: Check (*interval >= timeout - 1) && *interval <= timeout... failed
    interval error. got=3 expect=4-5
  log.c:98: Check ret == 0... failed
    update_and_check_interval for TEST_RECORD_02 failed. i=9
Test cache_one_slot...                          
[ OK ]
FAILED: 1 of 2 unit tests has failed.
      Start 32: flb-it-log_event_decoder
32/42 Test #32: flb-it-log_event_decoder .........   Passed    0.08 sec
      Start 33: flb-it-log_event_enco

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.

[nokute78]

Fix conflict.

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.