[vectorization] support forked pointer from loop body with control flow

[vfdff]

test: https://godbolt.org/z/bcYTW7KoT

void s1161_noReadWrite(int *Preds) {
  for (int i = 0; i < LEN_1D-1; ++i) {
    if (Preds[i] != 0)
      b[i] = c[i] + 1;
    else
      a[i] = i * i;
  }
}

This case is simplified from #64292,
but there is no pointer exists for both read and write, which will skip to check areDepsSafe.
I think this should be first supported.

[vfdff]

try to fix with https://reviews.llvm.org/D158493

[vfdff]

a new implementation solution on D158965