#371 Data comparer: "Only different values" is wrong with NULL values on H2

[PAscal]

for exemple when comparing
tab1 (emp, address)
moi, Paris
lui, Nice

tab2 (emp, adress)
moi, Paris
lui, <null>

comparer
columns: emp
aggregates: max(address)
only different values

should give:
emp,tab1_max(address),tab2_max(address)
moi, Paris, Paris
lui, Nice, <null> --> this line is not displayed