Constify most methods. We could have constified doInitialization and

Constify most methods. We could have constified doInitialization and
doFinalization too except that would have made them shadow, not override,
the parent class :-P.

Allow *any* constant cast expression between pointers and longs,
or vice-versa, or any widening (not just same-size) conversion that
isLosslesslyConvertibleTo approves. This fixes oopack.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7288 91177308-0d34-0410-b5e6-96231b3b80d8