Modified demo to work with non const Type parameters as is required by new

Modified demo to work with non const Type parameters as is required by new
type system. However most of these modifications were due to IRBuilder
(IRBuilderBase), not having been modified to NOT return such const qualified
free types. If IRBuilder does not change, as can also be seen in its
instruction creation methods, to use const free types, it may be useful to have
ExceptionDemo drop IRBuilder usage. Modifying builder.getInt32Ty() to
llvm::Type::getInt32Ty(builder.getContext()) is pretty ugly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134901 91177308-0d34-0410-b5e6-96231b3b80d8