[dump] Optimized dump state cli and modified tests to not use common data

[vivekrnv]

Why I did

Optimize Dump State Cli:
With the optimizations made, an entire run of "dump state" will only create 1 Sonicv2Connector Object and only call connect method once per db. i.e one DBConnector Object per DB

Test Stability:
Since the dump state tests are based on data (key and field-value pairs) any changes to those tables will lead to failure in dump state tests. Thus migrated the data_sources for dump_state_test & match_engine_tests from mock_tables to dump_input/ thus making them more stable.

How I did it

How to verify it

vkarri@230fae5c3278:/sonic/src/sonic-utilities$ pytest-3 tests/dump_tests/
========================================= test session starts ==========================================
platform linux -- Python 3.9.2, pytest-6.0.2, py-1.10.0, pluggy-0.13.0
rootdir: /sonic/src/sonic-utilities/tests, configfile: pytest.ini
plugins: pyfakefs-4.5.6, cov-2.10.1
collected 140 items                                                                                    

tests/dump_tests/dump_state_test.py .............                                                [  9%]
tests/dump_tests/match_engine_test.py .................................                          [ 32%]
tests/dump_tests/module_tests/copp_test.py ..........                                            [ 40%]
tests/dump_tests/module_tests/evpn_test.py ......                                                [ 44%]
tests/dump_tests/module_tests/fdb_test.py ............                                           [ 52%]
tests/dump_tests/module_tests/interface_test.py ..........                                       [ 60%]
tests/dump_tests/module_tests/port_test.py ......                                                [ 64%]
tests/dump_tests/module_tests/portchannel_member_test.py ...                                     [ 66%]
tests/dump_tests/module_tests/portchannel_test.py ....                                           [ 69%]
tests/dump_tests/module_tests/route_test.py ..........                                           [ 76%]
tests/dump_tests/module_tests/vlan_test.py .....................                                 [ 91%]
tests/dump_tests/module_tests/vxlan_tunnel_map_test.py .....                                     [ 95%]
tests/dump_tests/module_tests/vxlan_tunnel_test.py .......                                       [100%]

========================================= 140 passed in 1.04s ==========================================

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)

[lgtm-com]

This pull request introduces 1 alert when merging 642c6e6 into 9881f3e - view on LGTM.com

new alerts:

• 1 for Unused import

[SuvarnaMeenakshi]

lgtm