enable CompileTheWorld in non-hosted mode
Don't remove LoopExitNodes in UseTrappingNullChecksPhase.

--HG--
extra : rebase_source : daa674b9ba118eae9daa1255e97d820a52d51038
extra : amend_source : 91a0802576f1c21ba49c093164d1248bebea6183
mx: fix default handling of vm config and build type

--HG--
extra : rebase_source : 7ea362111b09d58f7f7c9fcb31f90c819ca72846