A << operation would be undefined for a bit-selecting
function because of a '1u' making it a 32-bit value
when it really needed to be a 64-bit value.  Trivial to fix
once I figured out what was going on.
clang static analzyer fixit.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@220022 91177308-0d34-0410-b5e6-96231b3b80d8