Well, if integer and tinyint should be considered equivalent, then solution is very simple. Just uncomment line 1530 in org.hibernate.dialect.Dialect.

// || isIntegral(typeCode1) && isIntegral(typeCode2)

It has been commented-out in commit 736dfac693ae56a854e620ee0ee02be31f88a4fe and replaced with

isSmallOrTinyInt(typeCode1) && isSmallOrTinyInt(typeCode2) //special case for HHH-15288 Closed migration

and six days later in commit 5089df203676657f51603d387fb55a65a916ac54 this added line has been removed.

After uncommenting this line, test case will not fail.