[llvm][AsmWriter] Don't skip zero-valued DwarfEnum MDField when ShouldSkipZero is not set (#126044)

I ran into this while working on a different patch where I'm emitting a
zero-valued DWARF enum field which shouldn't be skipped.

This patch checks the (currently unused) `ShouldSkipZero` before
deciding to skip printing this field. Based on git history this seems
like an oversight from the initial refactor that introduced this. We
have a similar check in `printInt`.

Wasn't sure how to best test this, but tests in an upcoming patch rely
on this functionality (see
https://github.com/llvm/llvm-project/pull/126045).

Currently the only place `ShouldSkipZero` is set to `false` is when
emitting the `DW_LANG_` enum. But the language codes start at `0x1`. So
it never exercised this codepath (and we should probably just make it
not pass this parameter).

0 files changed, 0 insertions, 0 deletions