[sonic-vlan.yang]: Correct Pattern for VLAN.

[praveen-li]

Changes:
-- Correct Pattern for VLAN.
-- Add Special Test support.
-- Add first special test to load VLAN 1-4094.
-- Add lanes in ports. [Need to make test pass with new test code.]
-- Make Sure None test gets no output from libyang while config load.

[yangModelTesting.py]: INCORRECT VLAN_NAME FIELD IN VLAN TABLE test.

Signed-off-by: Praveen Chaudhary pchaudhary@linkedin.com

- Why I did it
Changes:
-- Correct Pattern for VLAN.
-- Add Special Test support.
-- Add first special test to load VLAN 1-4094.
-- Add lanes in ports. [Need to make test pass with new test code.]
-- Make Sure None test gets no output from libyang while config load.

- How I did it

Changes:
-- Correct Pattern for VLAN.
-- Add Special Test support.
-- Add first special test to load VLAN 1-4094.
-- Add lanes in ports. [Need to make test pass with new test code.]
-- Make Sure None test gets no output from libyang while config load.

- How to verify it
Built with new Tests:

INFO:YANG-TEST:
------------------- Test 8: INCORRECT VLAN_NAME FIELD IN VLAN TABLE.---------------------
libyang[0]: Value "Vlan8090" does not satisfy the constraint "Vlan([0-9]{1,3}|[1-3][0-9]{3}|[4][0][0-8][0-9]|[4][0][9][0-4])" (range, length,
 or pattern). (path: /sonic-vlan:sonic-vlan/VLAN/VLAN_LIST[vlan_name='Vlan8090']/vlan_name)
INFO:YANG-TEST:INCORRECT VLAN_NAME FIELD IN VLAN TABLE. Passed

INFO:YANG-TEST:
------------------- Test 20: VLAN TEST.---------------------
INFO:YANG-TEST:All Test Passed

pchaudha@server05:/home/pchaudha/srcCode/azure_myforks/sonic-buildimage$ ls -l target/python-wheels/sonic_yang_models-1.0-py3-none-any.whl
-rw-r--r-- 1 pchaudha pchaudha 12645 Aug 12 14:07 target/python-wheels/sonic_yang_models-1.0-py3-none-any.whl
pchaudha@server05:/home/pchaudha/srcCode/azure_myforks/sonic-buildimage$ date
Wed Aug 12 14:30:07 PDT 2020
- Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006

This fix is to resolve a bug, which exists both in Master and 202006 branches.
- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[praveen-li]

retest mellanox please

[praveen-li]

Kindly review

[lguohan]

lgtm, can you enable the coverage for the unit test?