Handle non-default array bounds.

Handle non-default array bounds.

Some languages, e.g. Ada and Pascal, allow you to specify that the array bounds
are different from the default (1 in these cases). If we have a lower bound
that's non-default, then we emit the lower bound. We also calculate the correct
upper bound in those cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169484 91177308-0d34-0410-b5e6-96231b3b80d8