speed up route check 202405 v2

[deepak-singhal0408]

What I did
This PR fixes sonic-net/sonic-buildimage#18773 and sonic-net/sonic-buildimage#20648

Note: resubmitting the PR. The original PR was reverted due to PR check failure. The failure has been root caused and fixed via sonic-net/sonic-mgmt#16013

How I did it
Parallely execute route_check on each Asic.
Parallelly fetch ipv4 routes and ipv6 routes.

How to verify it
execute "time route_check.py" on T2 chassis having 32k v4+32k v6 routes.
Results:
Before:
Checking routes for namespaces: ['asic0', 'asic1']

real 3m16.387s
user 1m26.084s
sys 0m7.275s

After:
time route_check.py
real 1m30.675s
user 1m33.777s
sys 0m8.209s

Previous command output (if the output of a command-line utility has changed)
None

New command output (if the output of a command-line utility has changed)
None

[yejianquan]

Hi @deepak-singhal0408 , wonder why don't we merge this enhancement into master branch first?

[deepak-singhal0408]

Hi @deepak-singhal0408 , wonder why don't we merge this enhancement into master branch first?

Hold on @yejianquan.. its not merged yet..:) I am still testing this..
btw, Just to give some context,
Master and 202405 branch have conflicts and I will anyways have to create 2 different PRs.
Also 202405 branch this PR is needed by early next week to achieve better pass percentage on chassis.

[yejianquan]

Hi @deepak-singhal0408 , wonder why don't we merge this enhancement into master branch first?

Hold on @yejianquan.. its not merged yet..:) I am still testing this.. btw, Just to give some context, Master and 202405 branch have conflicts and I will anyways have to create 2 different PRs. Also 202405 branch this PR is needed by early next week to achieve better pass percentage on chassis.

@deepak-singhal0408 yeah separate PR works, I was asking because didn't see master PR.
Just converted it to draft in case someone wrongly merge it.

And just FYI that I also notice errlog for route_check time out in Cisco chassis test.

[deepak-singhal0408]

@bingwang-ms @yejianquan
here is the Master Branch PR #3678
The PR checker goes through now. Tried by updating the submodule in master branch.. results here. sonic-net/sonic-buildimage#21145

Since there will be cherry pick conflict. created this PR for 202405. This PR is needed asap to improve pass percentage on T2 DUTs running 202405. Thanks,