[llvm] [llvm] Remove `br i1 undef` from regression tests (PR #118419)

[Nuno Lopes via llvm-commits]

================
@@ -1,37 +1,41 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --function-signature
 ; RUN: opt < %s -S -passes=ipsccp | FileCheck %s
 
-; testf() performs an unconditional branch on undef, as such the testf() return
----------------
nunoplopes wrote:

pls don't remove this comment nor change the spirit of the test

https://github.com/llvm/llvm-project/pull/118419