Switch to using ImmutableDictionary inside SimpleVariableStore for basic variable types. We can't switch to using an ImmutableDictionary for the map type variables because then the original and the cloned SimpleVariableStore would have the same references to MapProxy objects which would mean writes to one SimpleVariableStore would affect the other.
Switch to using ImmutableDictionary inside SimpleVariableStore for
basic variable types. We can't switch to using an ImmutableDictionary
for the map type variables because then the original and the cloned
SimpleVariableStore would have the same references to MapProxy objects
which would mean writes to one SimpleVariableStore would affect the
other.

symbooglix/symbooglix,symbooglix/symbooglix,symbooglix/symbooglix