capability testing:
using Mellanox platform that actual has this API implemented:

syslog at init for the new PORT and LAG TPID attribute:

Jul 18 00:10:47.100902 str-sn3800-01 INFO syncd#supervisord: syncd Jul 18 00:10:47 NOTICE  SAI_UTILS: mlnx_sai_utils.c[615]- mlnx_query_attr_api_get_metadata: Failed to find vendor data - attribute is not implemented
Jul 18 00:10:47.100902 str-sn3800-01 INFO syncd#supervisord: syncd Jul 18 00:10:47 NOTICE  SAI_UTILS: mlnx_sai_utils.c[668]- mlnx_sai_query_attribute_capability_impl: Querying attribute capabilities for [SAI_OBJECT_TYPE_PORT:SAI_PORT_ATTR_TPID]
Jul 18 00:10:47.100902 str-sn3800-01 INFO syncd#supervisord: syncd Jul 18 00:10:47 NOTICE  SAI_UTILS: mlnx_sai_utils.c[683]- mlnx_sai_query_attribute_capability_impl: Got attribute capability [SAI_OBJECT_TYPE_PORT:SAI_PORT_ATTR_TPID]: create_implemented: false, set_implemented: false, get_implemented: false
Jul 18 00:10:47.101041 str-sn3800-01 NOTICE swss#orchagent: :- init: port TPID capability 0
Jul 18 00:10:47.101493 str-sn3800-01 INFO syncd#supervisord: syncd Jul 18 00:10:47 NOTICE  SAI_UTILS: mlnx_sai_utils.c[615]- mlnx_query_attr_api_get_metadata: Failed to find vendor data - attribute is not implemented
Jul 18 00:10:47.101493 str-sn3800-01 INFO syncd#supervisord: syncd Jul 18 00:10:47 NOTICE  SAI_UTILS: mlnx_sai_utils.c[668]- mlnx_sai_query_attribute_capability_impl: Querying attribute capabilities for [SAI_OBJECT_TYPE_LAG:SAI_LAG_ATTR_TPID]
Jul 18 00:10:47.101493 str-sn3800-01 INFO syncd#supervisord: syncd Jul 18 00:10:47 NOTICE  SAI_UTILS: mlnx_sai_utils.c[683]- mlnx_sai_query_attribute_capability_impl: Got attribute capability [SAI_OBJECT_TYPE_LAG:SAI_LAG_ATTR_TPID]: create_implemented: false, set_implemented: false, get_implemented: false
Jul 18 00:10:47.101606 str-sn3800-01 NOTICE swss#orchagent: :- init: LAG TPID capability 0
Jul 18 00:10:47.102653 str-sn3800-01 NOTICE swss#orchagent: :- loadRedisScript: lua script loaded, sha: 88270a7c5c90583e56425aca8af8a4b8c39fe757
Jul 18 00:10:47.103315 str-sn3800-01 NOTICE swss#orchagent: :- loadRedisScript: lua script loaded, sha: 88270a7c5c90583e56425aca8af8a4b8c39fe757
Jul 18 00:10:47.103315 str-sn3800-01 NOTICE swss#orchagent: :- init: mellanox switch capability:
Jul 18 00:10:47.103315 str-sn3800-01 NOTICE swss#orchagent: :- init:     ACL_TABLE_MIRROR: yes
Jul 18 00:10:47.103315 str-sn3800-01 NOTICE swss#orchagent: :- init:     ACL_TABLE_MIRRORV6: yes
Jul 18 00:10:47.104013 str-sn3800-01 NOTICE swss#orchagent: :- init: Get ACL entry priority values, min: 0, max: 262141
Jul 18 00:10:47.109835 str-sn3800-01 NOTICE swss#orchagent: :- loadRedisScript: lua script loaded, sha: b31aeab81e89aa75a65014207422ca913b2e4696
Jul 18 00:10:47.110145 str-sn3800-01 NOTICE swss#orchagent: :- loadRedisScript: lua script loaded, sha: 66d494cd1325c6eee7d4959e18cfb2b0f672cdad

sairedis record:
2020-07-18.00:10:47.090124|q|attribute_enum_values_capability|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|SAI_DEBUG_COUNTER_ATTR_OUT_DROP_REASON_LIST=100
2020-07-18.00:10:47.090844|Q|attribute_enum_values_capability|SAI_STATUS_SUCCESS|SAI_DEBUG_COUNTER_ATTR_OUT_DROP_REASON_LIST=0:null
2020-07-18.00:10:47.090975|q|object_type_get_availability|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|SAI_DEBUG_COUNTER_ATTR_TYPE=SAI_DEBUG_COUNTER_TYPE_SWITCH_IN_DROP_REASONS
2020-07-18.00:10:47.091618|Q|object_type_get_availability|SAI_STATUS_SUCCESS|COUNT=31
2020-07-18.00:10:47.091800|q|object_type_get_availability|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|SAI_DEBUG_COUNTER_ATTR_TYPE=SAI_DEBUG_COUNTER_TYPE_PORT_OUT_DROP_REASONS
2020-07-18.00:10:47.092412|Q|object_type_get_availability|SAI_STATUS_ATTR_NOT_SUPPORTED_0|COUNT=94276721684928
2020-07-18.00:10:47.092552|q|object_type_get_availability|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|SAI_DEBUG_COUNTER_ATTR_TYPE=SAI_DEBUG_COUNTER_TYPE_SWITCH_OUT_DROP_REASONS
2020-07-18.00:10:47.093239|Q|object_type_get_availability|SAI_STATUS_SUCCESS|COUNT=31
2020-07-18.00:10:47.093412|q|object_type_get_availability|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|SAI_DEBUG_COUNTER_ATTR_TYPE=SAI_DEBUG_COUNTER_TYPE_PORT_IN_DROP_REASONS
2020-07-18.00:10:47.094137|Q|object_type_get_availability|SAI_STATUS_ATTR_NOT_SUPPORTED_0|COUNT=140526232090536
2020-07-18.00:10:47.100247|q|attribute_capability|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|OBJECT_TYPE=SAI_OBJECT_TYPE_PORT|ATTR_ID=SAI_PORT_ATTR_TPID
2020-07-18.00:10:47.100902|Q|attribute_capability|SAI_STATUS_SUCCESS|OBJECT_TYPE=SAI_OBJECT_TYPE_PORT|ATTR_ID=SAI_PORT_ATTR_TPID|CREATE_IMP=false|SET_IMP=false|GET_IMP=false
2020-07-18.00:10:47.100961|q|attribute_capability|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|OBJECT_TYPE=SAI_OBJECT_TYPE_LAG|ATTR_ID=SAI_LAG_ATTR_TPID
2020-07-18.00:10:47.101486|Q|attribute_capability|SAI_STATUS_SUCCESS|OBJECT_TYPE=SAI_OBJECT_TYPE_LAG|ATTR_ID=SAI_LAG_ATTR_TPID|CREATE_IMP=false|SET_IMP=false|GET_IMP=false
2020-07-18.00:10:47.103305|g|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|SAI_SWITCH_ATTR_ACL_ENTRY_MINIMUM_PRIORITY=4|SAI_SWITCH_ATTR_ACL_ENTRY_MAXIMUM_PRIORITY=2189608472
2020-07-18.00:10:47.103849|G|SAI_STATUS_SUCCESS|SAI_SWITCH_ATTR_ACL_ENTRY_MINIMUM_PRIORITY=0|SAI_SWITCH_ATTR_ACL_ENTRY_MAXIMUM_PRIORITY=262141
2020-07-18.00:10:47.103907|g|SAI_OBJECT_TYPE_SWITCH:oid:0x21000000000000|SAI_SWITCH_ATTR_MAX_ACL_ACTION_COUNT=2
2020-07-18.00:10:47.104357|G|SAI_STATUS_SUCCESS|SAI_SWITCH_ATTR_MAX_ACL_ACTION_COUNT=28


Redis STATE DB:
admin@str-sn3800-01:/var/log/swss$ redis-cli -n 6
127.0.0.1:6379[6]> hgetall "SWITCH_CAPABILITY|switch"
 1) "PORT_TPID_CAPABLE"
 2) "false"
 3) "LAG_TPID_CAPABLE"
 4) "false"
 5) "MIRROR"
 6) "true"
 7) "MIRRORV6"
 8) "true"
 9) "ACL_ACTIONS|INGRESS"
10) "PACKET_ACTION,REDIRECT_ACTION,MIRROR_INGRESS_ACTION"
11) "ACL_ACTIONS|EGRESS"
12) "PACKET_ACTION,MIRROR_EGRESS_ACTION"
13) "ACL_ACTION|PACKET_ACTION"
14) "DROP,FORWARD"
127.0.0.1:6379[6]>