[clang] Switch builtin strings to use string tables (PR #118734)

[Chandler Carruth via cfe-commits]

chandlerc wrote:

> > > LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-win` running on `sie-win-worker` while building `clang` at step 7 "test-build-unified-tree-check-all".
> > > Full details are available at: [lab.llvm.org/buildbot#/builders/46/builds/9169](https://lab.llvm.org/buildbot/#/builders/46/builds/9169)
> > 
> > 
> > This is a Windows build bot with a version of MSVC '19.28.29924.0' -- that's not even one of the numbers listed here: [en.wikipedia.org/wiki/Microsoft_Visual_C%2B%2B#Internal_version_numbering](https://en.wikipedia.org/wiki/Microsoft_Visual_C%2B%2B#Internal_version_numbering)
> > (edit because I can't count)
> > Looks like it might be a build after 16.9.19 which is listed as 19.28.29923. Not sure what to do debug this... @zmodem maybe has some idea?
> > It doesn't seem to be the issue I know about on older versions of MSVC as there are no errors on the long string literal. But somehow it seems to be miscompiling the string literals?
> 
> I manage this build bot, is there anything I can do to help you debug this problem? We use this build as our "blessed" build internally for building on Windows.

Some indication of what's causing this? Or maybe whether there are any other versions of MSVC available with different results?

I don't have a Windows machine to debug on at all, but the premerge windows build was successful, so it seems to work on some builders but not others. So far I don't have any other failures to look at to cross-compare...

https://github.com/llvm/llvm-project/pull/118734