[202205] [generate_dump] Revert "[202205] Revert the show-techsupport optimization PR's" and fix the empty /dump folder

[vadymhlushko-mlnx]

What I did

Revert of the Revert " [202205] Revert the show-techsupport optimization PR's
Also, a fix for the degradation - an empty /var/dump/sonic_dump..../dump folder produced by the show_techsupport script.

How I did it

Delete the line of the code which removes all generated data: commit

1577    $RM $V -rf $TARDIR
1578    $MKDIR $V -p $TARDIR
1579    $MKDIR $V -p $LOGDIR

How to verify it

1. Take an image with the original generate_dump script (with no optimization)
2. Run on the switch show techsupport command and take the output archive from /var/dump/sonic_dump...tar.gz
3. Take and image with this PR included (with generate_dump optimization)
4. Run on the switch show techsupport command and take the output archive from /var/dump/sonic_dump...tar.gz
5. Compare archives from step 2 and step 4 by using Linux tool ncdu

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)

[dgsudharsan]

The change creates symlinks and avoids duplicate copy inside the tar. The final tar option has "-h" which will undo this change. Can we overcome this?