ignore model assignment for internal function ARRAY_EXT.
ignore model assignment for internal function ARRAY_EXT.

This fixes https://gitlab.com/sosy-lab/software/cpachecker/-/issues/857 .

sosy-lab/java-smt,sosy-lab/java-smt,sosy-lab/java-smt,sosy-lab/java-smt,sosy-lab/java-smt