[clang] [llvm] [Clang][ARM] Fix immediate range for NEON widening left-shifts (PR #212459)

[David Green via cfe-commits]

davemgreen wrote:

Oh I think I read it wrong, with the two different type sizes. This now limits the range to match gcc, so we no longer support constants from n+1..2n-1? So the shift cannot be out of range.

There might be people who were trying to use the old range but if we are matching GCC it sounds OK.

https://github.com/llvm/llvm-project/pull/212459