Combine two patterns into one.

service tool exit code handling changes

CentOS and RHEL have some verisons which set service.rdma to refuse
 manual start/stop commands.
 This PR:

Adds an optional exit code ignore in addition to 0 for success.
Adds a constant to service for a systemd exit code that the setup
  for testpmd will encounter nonfatally on some platforms.

Fix test cases issues. (microsoft#1839)

* Remove serial console log check from verify_grub, the logic is in
verify_serial_console_is_enabled

* Reboot vm after unbind time clock source to bring the previous one back.

Azure: truncate long names better.

The resource group name limits to 80 (90 max) and vm name limits to
50 (64 max). the vm name will attach suffix, so it limits more.

The leading "lisa-" keeps in the name for two reasons.
1. It's needed to identify auto created envs, and delete by pipelines.
2. It avoids the random start chars like "-". It causes resource
    creation failure, because Azure accept name starts with chars only.

process: fix regression breaks commands.

DPDK: Add multiprocess test from v2 (microsoft#1792)

- Adds test using the multiprocess client-server app

wala: fix error on get python version.

gpu: fix failure and add pytorch test case

Add case verify_boot_error_fail_warnings.

DPDK-OVS test for Debian+Ubuntu

    - initial OVS test implemented for Debian+Ubuntu
    - Redhat and SUSE can be supported eventually, not implemented yet.