Add TCP keepalive warnings test to TAP test groups

Added reg_test_5212_tcp_keepalive_warnings-t to the default test group
to ensure the new TCP keepalive warnings test is included in automated testing.

test/tap/groups/groups.json

@@ -31,6 +31,7 @@
   "mysql-reg_test_4716_single_semicolon-t" : [ "default-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1" ],
   "mysql-reg_test_4723_query_cache_stores_empty_result-t" : [ "default-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1" ],
   "mysql-reg_test_4867_query_rules-t" : [ "default-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1" ],
+  "reg_test_5212_tcp_keepalive_warnings-t" : [ "default-g1" ],
   "mysql-set_transaction-t" : [ "default-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1" ],
   "mysql-sql_log_bin-error-t" : [ "default-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1" ],
   "mysql_stmt_send_long_data_large-t" : [ "default-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1" ],