Disable Dalvik spam by default

Reverse the logic: use "dalvik.vm.debug.alloc=1" to see these lines.

Change-Id: Id58de1dd09467c2327f76d37eeb926b712d6af52
Reject dex files that attempt to use unspecified class access flags

Change-Id: Ib1ecf3dfe1856a9014c2e9b0d6a1725ba7617f98
Move verification of class access flags to libdex

Change-Id: I020a168cfff46e319b0bebb6c7477f0b4139c6de