Flush RESTAPI db in fast-reboot shutdown path

[bingwang-ms]

What I did

The PR is to flush RESTAPI_DB in the fast-reboot shutdown path.
After PR #2365, the table is not cleared because the WARM_RESTART_ENABLE_TABLE|system is set to true.
So below code in swss.sh doesn't do the db flush.
https://github.com/sonic-net/sonic-buildimage/blob/bdef73ea963064cdc9fbebb63ac381440c0fafd6/files/scripts/swss.sh#L168C1-L181C7

if [[ x"$WARM_BOOT" != x"true" ]]; then
        debug "Flushing APP, ASIC, COUNTER, CONFIG, and partial STATE databases ..."
        $SONIC_DB_CLI APPL_DB FLUSHDB
        $SONIC_DB_CLI ASIC_DB FLUSHDB
        $SONIC_DB_CLI COUNTERS_DB FLUSHDB
        $SONIC_DB_CLI FLEX_COUNTER_DB FLUSHDB
        $SONIC_DB_CLI GB_ASIC_DB FLUSHDB
        $SONIC_DB_CLI GB_COUNTERS_DB FLUSHDB
        $SONIC_DB_CLI RESTAPI_DB FLUSHDB
        clean_up_tables STATE_DB "'PORT_TABLE*', 'MGMT_PORT_TABLE*', 'VLAN_TABLE*', 'VLAN_MEMBER_TABLE*', 'LAG_TABLE*', 'LAG_MEMBER_TABLE*', 'INTERFACE_TABLE*', 'MIRROR_SESSION*', 'VRF_TABLE*', 'FDB_TABLE*', 'FG_ROUTE_TABLE*', 'BUFFER_POOL*', 'BUFFER_PROFILE*', 'MUX_CABLE_TABLE*', 'ADVERTISE_NETWORK_TABLE*', 'VXLAN_TUNNEL_TABLE*', 'VNET_ROUTE*', 'MACSEC_PORT_TABLE*', 'MACSEC_INGRESS_SA_TABLE*', 'MACSEC_EGRESS_SA_TABLE*', 'MACSEC_INGRESS_SC_TABLE*', 'MACSEC_EGRESS_SC_TABLE*', 'VRF_OBJECT_TABLE*', 'VNET_MONITOR_TABLE*', 'BFD_SESSION_TABLE*'"
        $SONIC_DB_CLI APPL_STATE_DB FLUSHDB
        rm -rf /tmp/cache
    fi

How I did it

Flush RESTAPI_DB in the fast-reboot shutdown path.

How to verify it

We have a sonic-mgmt test case restapi/test_restapi.py::test_check_reset_status to cover the feature.
The test can pass after this change.

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

N/A

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

N/A

[vaibhavhd]

This will get cleared for NVIDIA's warmboot (fastfast-reboot). I think that is not expected.

Should this check be restricted to fast-reboot? @prsunny ?

[bingwang-ms]

I updated the code. Now it's limited to fast-reboot only.

[bingwang-ms]

/azp run

[azure-pipelines]

No commit pushedDate could be found for PR 2917 in repo sonic-net/sonic-utilities

[jarias-lfx]

/easycla

[bingwang-ms]

/easycla

[bingwang-ms]

MSFT ADO: https://msazure.visualstudio.com/One/_workitems/edit/24594572

[bingwang-ms]

PR filed for 202205 branch #2921