PR that enables indyLambda for building scala/scala: scala/scala#4594

[solved in pr 4599] a number of tests for reify crash the backend at runtime:

• run/reify_properties.scala
• run/reify_newimpl_52.scala
• run/reify_properties.scala
• run/reify_fors_oldpatmat.scala
• run/reify_newimpl_51.scala
• run/reify_fors_newpatmat.scala
• run/reify_sort1.scala
• run/reify_csv.scala
• run/reify_for1.scala

[still to do] another issue: the old optimizer seems to fail when the scala library is compiled with indyLambda, e.g., it cannot inline List.foreach. That causes a number of test failures:

• run/t7008-scala-defined/Test_3.scala
• run/private-inline.scala
• jvm/patmat_opt_ignore_underscore/test.scala
• jvm/patmat_opt_no_nullcheck/test.scala
• run/elidable-opt.scala started producing inliner warnings