[llvm] [LoopVectorize] Don't replicate blocks with optsize (PR #129265)

[John Brawn via llvm-commits]

john-brawn-arm wrote:

The new implementation is a bit different to the old one in how it's affected by the various flags that force things.

Previously:
 * -force-tail-folding-style would force scalarization to happen
 * -force-vector-width had no effect

Now:
 * -force-tail-folding-style has no effect
 * -force-vector-width forces the vector width, even if it required replicating blocks

This means that the test changes are a bit different.

https://github.com/llvm/llvm-project/pull/129265