[ValueTracking] Don't special case wrapped ConstantRanges; NFCI
Use `getUnsignedMax` directly instead of special casing a wrapped
ConstantRange.
The previous code would have been "buggy" (and this would have been a
semantic change) if LLVM allowed !range metadata to denote full
ranges. E.g. in
%val = load i1, i1* %ptr, !range !{i1 1, i1 1} ;; == full set
ValueTracking would conclude that the high bit (IOW the only bit) in
%val was zero.
Since !range metadata does not allow empty or full ranges, this change
is just a minor stylistic improvement.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251380
91177308-0d34-0410-b5e6-
96231b3b80d8