Description
Missing vxlan_decap.json.j2 when runing test case "wr_arp" in t0 topology; master on Jul/14/2020 commit.

Steps to reproduce the issue:

1. alan_chen@3c76e330b7bd:~/sonic-mgmt/ansible$ ansible-playbook -i veos -l lab-esc601-32-MAX test_sonic.yml -e testbed_name=vms-601-t0 -e testbed_file=testbed.csv -e testbed_type=t0 -e ptf_host=ptf_vms6-1 -vvvv -e sonicadmin_user=admin -e sonicadmin_password=password -e testcase_name=wr_arp

Describe the results you received:
TASK [test : Render DUT parameters to json file for the test] ***************************************************************
task path: /var/alan_chen/sonic-mgmt/ansible/roles/test/tasks/wr_arp.yml:98
Thursday 27 August 2020 09:41:20 +0000 (0:00:00.795) 0:05:32.660 *******
<192.168.3.19> ESTABLISH SSH CONNECTION FOR USER: root
<192.168.3.19> SSH: EXEC sshpass -d10 ssh -vvv -o ControlMaster=auto -o ControlPersist=120s -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o StrictHostKeyChecking=no -o 'User="root"' -o ConnectTimeout=10 -o ControlPath=/var/alan_chen/.ansible/cp/b311b5f99c 192.168.3.19 '/bin/sh -c '"'"'( umask 77 && mkdir -p "echo $HOME/.ansible/tmp"&& mkdir $HOME/.ansible/tmp/ansible-tmp-1598521281.02-57324-102122124294527 && echo ansible-tmp-1598521281.02-57324-102122124294527="echo $HOME/.ansible/tmp/ansible-tmp-1598521281.02-57324-102122124294527" ) && sleep 0'"'"''
...
...
...
fatal: [lab-esc601-32-MAX -> 192.168.3.19]: FAILED! => {
"changed": false,
"msg": "Could not find or access 'vxlan_decap.json.j2'\nSearched in:\n\t/var/alan_chen/sonic-mgmt/ansible/roles/test/templates/vxlan_decap.json.j2\n\t/var/alan_chen/sonic-mgmt/ansible/roles/test/vxlan_decap.json.j2\n\t/var/alan_chen/sonic-mgmt/ansible/roles/test/tasks/templates/vxlan_decap.json.j2\n\t/var/alan_chen/sonic-mgmt/ansible/roles/test/tasks/vxlan_decap.json.j2\n\t/var/alan_chen/sonic-mgmt/ansible/templates/vxlan_decap.json.j2\n\t/var/alan_chen/sonic-mgmt/ansible/vxlan_decap.json.j2 on the Ansible Controller.\nIf you are using a module and expect the file to exist on the remote, see the remote_src option"
}