Fix connection error message regexp for Mysql2 #965

Job	Run time
Ruby 3.2 / semian	3m 35s
Ruby 3.1 / semian	3m 15s
Ruby 3.0 / semian	3m 42s
Ruby 3.2 / grpc	7m 50s
Ruby 2.7 / semian	3m 10s
Ruby 3.2 / mysql2	2m 33s
Ruby 3.2 / net_http	1m 21s
Ruby 3.2 / rails_mysql2	1m 26s
Ruby 3.2 / rails_trilogy	1m 57s
Ruby 3.2 / redis_4	1m 32s
Ruby 3.2 / redis_5	1m 35s
Ruby 3.2 / redis_client	1m 26s
Ruby 3.2 / activerecord_trilogy_adapter	2m 39s
Ruby 3.1 / grpc	1m 18s
Ruby 3.1 / mysql2	1m 56s
Ruby 3.1 / net_http	1m 20s
Ruby 3.1 / rails_mysql2	1m 19s
Ruby 3.1 / rails_trilogy	1m 51s
Ruby 3.1 / redis_4	1m 33s
Ruby 3.1 / redis_5	1m 30s
Ruby 3.1 / redis_client	1m 59s
Ruby 3.1 / activerecord_trilogy_adapter	2m 44s
Ruby 3.0 / grpc	1m 17s
Ruby 3.0 / mysql2	2m 5s
Ruby 3.0 / net_http	1m 8s
Ruby 3.0 / rails_mysql2	1m 51s
Ruby 3.0 / rails_trilogy	1m 57s
Ruby 3.0 / redis_4	1m 28s
Ruby 3.0 / redis_5	1m 34s
Ruby 3.0 / redis_client	1m 33s
Ruby 3.0 / activerecord_trilogy_adapter	2m 3s
Ruby 2.7 / grpc	1m 37s
Ruby 2.7 / mysql2	1m 25s
Ruby 2.7 / net_http	1m 9s
Ruby 2.7 / rails_mysql2	1m 20s
Ruby 2.7 / rails_trilogy	2m 8s
Ruby 2.7 / redis_4	1m 19s
Ruby 2.7 / redis_5	1m 20s
Ruby 2.7 / redis_client	1m 19s
Ruby 2.7 / activerecord_trilogy_adapter	2m 11s
	1h 20m 15s

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