Implement maps for CVC4, now that it supports constant arrays
Implement maps for CVC4, now that it supports constant arrays

reactivate tests for CVC4, if available. Remove non-linear testcase that
worked only on z3 (SumAndMax)

epfl-lara/stainless,epfl-lara/stainless,epfl-lara/stainless,epfl-lara/stainless