[clang] [llvm] [LLVM][DWARF] Fix accelerator table switching between CU and TU (PR #77511)

[Rainer Orth via cfe-commits]

rorth wrote:

However, the patch broke the [Solaris/sparcv9 buildbot](https://lab.llvm.org/buildbot/#/builders/72/builds/1834):
```
llc: error: unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.
```
The bot is configured to do a Sparc-only build.

https://github.com/llvm/llvm-project/pull/77511