Table simpletest626961 simpletest_test_id doesn't exists

Error: Table simpletest626961simpletest_test_id doesn't exists.

This is the order of mysql queries sent when running BlockTestCase test:

$ ./run_test.sh debug BlockTestCase 2>&1 | grep simpletest_test_id
write(4, "INSERT INTO simpletest_test_id (test_id) VALUES (default)", 62) = 62
write(4, "UPDATE simpletest_test_id SET last_prefix = 'simpletest626961' WHERE test_id = 121", 87) = 87
write(4, "SELECT COUNT(test_id) FROM simpletest626961simpletest_test_id", 66) = 66

write(4, "DELETE FROM simpletest626961simpletest_test_id", 51) = 51
write(4, "UPDATE simpletest_test_id SET last_prefix = 'simpletest239001' WHERE test_id = 121", 87) = 87
write(4, "SELECT COUNT(test_id) FROM simpletest239001simpletest_test_id", 66) = 66
write(4, "DELETE FROM simpletest239001simpletest_test_id", 51) = 51
write(2, "Test _db_query() failed: Table 'simpletest626961simpletest_test_id' doesn't e"..., 262Test _db_query() failed: Table 'simpletest626961simpletest_test_id' doesn't exist                                                                 [error]
query: SELECT COUNT(test_id) FROM simpletest626961simpletest_test_id
write(2, "Test _db_query() failed: Table 'simpletest626961simpletest_test_id' doesn't e"..., 247Test _db_query() failed: Table 'simpletest626961simpletest_test_id' doesn't exist                                                                 [error]
query: DELETE FROM simpletest626961simpletest_test_id
write(2, "Test _db_query() failed: Table 'simpletest239001simpletest_test_id' doesn't e"..., 262Test _db_query() failed: Table 'simpletest239001simpletest_test_id' doesn't exist                                                                 [error]
query: SELECT COUNT(test_id) FROM simpletest239001simpletest_test_id
write(2, "Test _db_query() failed: Table 'simpletest239001simpletest_test_id' doesn't e"..., 247Test _db_query() failed: Table 'simpletest239001simpletest_test_id' doesn't exist                                                                 [error]
query: DELETE FROM simpletest239001simpletest_test_id
write(4, "SELECT COUNT(test_id) FROM simpletest_test_id", 50) = 50
write(4, "DELETE FROM simpletest_test_id", 35) = 35

I don't see any query with table creation.
Or maybe it shouldn't be prefixed at all?

I've version with the following patches:
#1319736: SimpleTest: When using drupalGet to send the cookie, it's sending Cookie header twice, so the $_COOKIE is not valid
#1781018: Simpletest dropping the real Drupal tables instead of simpletest tables
#803026: Fatal error on simpletest: Unsupported operand types in form.inc on line 518
#943572: Verbose logging fails when 'simpletest' files directory does not exist
but these shouldn't affect much.