Any VPlan we generate that contains a replicator region will result in
replicated blocks in the output, causing a large code size increase.
Reject such VPlans when optimizing for size, as the code size impact is
usually worse than having a scalar epilogue, which we already forbid
with optsize.
This change requires a lot of test changes. For tests of optsize
specifically I've updated the test with the new output, otherwise the
tests have been adjusted to not rely on optsize.
Fixes#66652
eafbb879f6