[llvm] [SandboxIR] Update visibility of IR constructors. (PR #98107)

[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 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/1282

Here is the relevant piece of the build log for the reference:
```
Step 6 (test-build-unified-tree-check-all) failure: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
1.263 [60/18/1] Linking CXX executable tools/clang/unittests/Format/FormatTests
1.472 [59/18/2] Linking CXX executable tools/clang/unittests/Basic/BasicTests
command timed out: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1202.153862

```

https://github.com/llvm/llvm-project/pull/98107