most tests are working

src/main/scala/leon/solvers/z3/FairZ3Solver.scala

src/main/scala/leon/verification/AnalysisPhase.scala

src/main/scala/leon/xlang/ImperativeCodeElimination.scala

...rces/regression/verification/xlang/invalid/MyTuple1.scala

...rces/regression/verification/xlang/invalid/MyTuple2.scala

...rces/regression/verification/xlang/invalid/MyTuple3.scala

...ources/regression/verification/xlang/valid/MyTuple1.scala

...ources/regression/verification/xlang/valid/MyTuple3.scala

...ources/regression/verification/xlang/valid/MyTuple4.scala

...ources/regression/verification/xlang/valid/MyTuple5.scala

...ources/regression/verification/xlang/valid/MyTuple6.scala

.../leon/test/verification/XLangVerificationRegression.scala