[llvm] [MC] Avoid DWARF emission after inline asm errors (PR #228707)

[Mathew Joseph via llvm-commits]

mathew1046 wrote:

CI exposed a regression in the first version of this fix: returning early from `MCStreamer::finish()` suppressed existing frame diagnostics, causing four unrelated CFI tests to fail.

I corrected the implementation by moving the error guard to `MCObjectStreamer::finishImpl()`. `MCStreamer::finish()` now performs its normal unfinished-frame validation and diagnostics, while object and DWARF emission are skipped only after an error has already been recorded.

I also fixed the regression test final newline.

Validation after the correction:
- The new inline-assembly regression passes with assertions-enabled `llc`.
- The X86 `cfi-label.s` checks pass.
- All three `cfi-scope-errors.s` checks pass.
- The X86-only local build could not run the ARM and AArch64 tests, which remain covered by CI.

The corrected commit is `d173e3b1a056`.

https://github.com/llvm/llvm-project/pull/228707