Improved the PushAssumptionToEnvironmentVisitor to also use the new immutable NonRecursiveEnvironment by adding a Builder for NonRecursiveEnvironments to allow for adding a more precise special case handling for extracting environment information from equality formulas.

git-svn-id: https://svn.sosy-lab.org/software/cpachecker/trunk@12948 4712c6d2-40bb-43ae-aa4b-fec3f1bdfe4c