[lldb][Target] Allow eLanguageTypeAssembly to use ScratchTypeSystemClang (#183771)

After cleaning up some of our `LanguageType`/`SourceLangage`
round-tripping (see `7f51a2a47d2e706d04855b0e41690ebafa2b3238`), a CU
with `DW_LANG_MIPS_Assembler` will get a language type of
`eLanguageTypeAssembly` (as opposed to `eLanguageTypeMipsAssembler`).
Reason being that there is no `DW_LNAME_` (DWARFv6 language code) for
`MIPS Assembler`, only for generic `Assembly`. So it's not possible to
round-trip cleanly between pre-DWARFv6 and DWARFv6 language codes, which
LLDB relies on for storing language types (and will lean into more
heavily in the future). This broke a special provision we have where we
allow `ScratchTypeSystemClang` to be used when evaluating expressions in
assembly CUs (i.e., CUs where the debug-info explicitly sets the
language to assembly).

If we ever want to distinguish MIPS from other Assembly, the proper way
to do so is introduce a `DW_LNAME_Mips_Assembler`. For now, this patch
adds another case for `eLanguageTypeAssembly` in
`GetScratchTypeSystemForLanguage`.

The test is a bit quirky because it checks for error messages in all
cases. For the `TypeSystem`s to exist we would have to initialize the
`TypeSystem` plugins, which I couldn't find a precedent for. But happy
to hear other suggestions for testing

Fixes https://github.com/llvm/llvm-project/issues/183388
3 files changed
tree: 659b6cf7249e764d74d44582f68d73d0cb3bb381
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libsycl/
  16. libunwind/
  17. lld/
  18. lldb/
  19. llvm/
  20. llvm-libgcc/
  21. mlir/
  22. offload/
  23. openmp/
  24. orc-rt/
  25. polly/
  26. runtimes/
  27. third-party/
  28. utils/
  29. .clang-format
  30. .clang-format-ignore
  31. .clang-tidy
  32. .git-blame-ignore-revs
  33. .gitattributes
  34. .gitignore
  35. .mailmap
  36. CODE_OF_CONDUCT.md
  37. CONTRIBUTING.md
  38. LICENSE.TXT
  39. pyproject.toml
  40. README.md
  41. SECURITY.md
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