[llvm] Branch folding: Avoid infinite loop with indirect target blocks (PR #96956)

[via llvm-commits]

v01dXYZ wrote:

About the comment explaining why it's necessary to check Fallthrough not being EHPad or Indirect Target, I kept the following wording `even if in the case of EHPad that appears not to be happening anymore`. It seems to be wrong as the test `branchfolding-catchpads.ll` will inf loop if removing the check. So it still happens. @andykaylor do you think it's fair to remove this part from the comment ?

https://github.com/llvm/llvm-project/pull/96956