Fix separate bind:group with one array

[Th0rN13]

Fix #4397

This is two issues:

• push to array add duplicated values, i use Set
• unchecked values need to compare to previous values, so need store old values for each group, i use Map

Add two tests:

• one check what check\uncheck work with binded array
• another: identical values in other group does not affect the first

[pushkine]

you're introducing a memory leak with the map of array to sets

[Conduitry]

Closing in favor of #4877.