[llvm] [VPlan] Fix isLatch to handle BranchOnTwoConds, check verifier.(NFC) (PR #192808)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `arc-builder` running on `arc-worker` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/31232

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
...
35.044 [2/14/111] Linking CXX executable bin/llvm-ir2vec
35.119 [2/13/112] Linking CXX executable bin/llvm-isel-fuzzer
35.171 [2/12/113] Linking CXX executable bin/llvm-gsymutil
35.323 [2/11/114] Linking CXX executable bin/llvm-exegesis
35.533 [2/10/115] Linking CXX executable bin/clang-check
36.658 [2/9/116] Linking CXX executable bin/llvm-split
38.261 [2/8/117] Linking CXX executable bin/llvm-opt-fuzzer
39.068 [2/7/118] Linking CXX executable bin/llvm-lto2
39.304 [2/6/119] Linking CXX executable bin/llvm-reduce
39.485 [2/5/120] Linking CXX executable bin/c-index-test
command timed out: 1200 seconds without output running [b'ninja', b'-j', b'16'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1240.337911

```

</details>

https://github.com/llvm/llvm-project/pull/192808