new regression tests on Tuple in purescala

.../regression/verification/purescala/invalid/MyTuple1.scala

.../regression/verification/purescala/invalid/MyTuple2.scala

.../regression/verification/purescala/invalid/MyTuple3.scala

...es/regression/verification/purescala/valid/MyTuple1.scala

...es/regression/verification/purescala/valid/MyTuple2.scala

...es/regression/verification/purescala/valid/MyTuple3.scala

...es/regression/verification/purescala/valid/MyTuple4.scala

...es/regression/verification/purescala/valid/MyTuple5.scala

...es/regression/verification/purescala/valid/MyTuple6.scala