Rollup merge of #136640 - Zalathar:debuginfo-align-bits, r=compiler-errors

Debuginfo for function ZSTs should have alignment of 8 bits, not 1 bit

In #116096, function ZSTs were made to have debuginfo that gives them an alignment of “1”. But because alignment in LLVM debuginfo is denoted in *bits*, not bytes, this resulted in an alignment specification of 1 bit instead of 1 byte.

I don't know whether this has any practical consequences, but I noticed that a test started failing when I accidentally fixed the mistake while working on #136632, so I extracted the fix (and the test adjustment) to this PR.

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -633,7 +633,7 @@ impl<'ll, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                 true,
                 DIFlags::FlagZero,
                 argument_index,
-                align.bytes() as u32,
+                align.bits() as u32,
             )
         }
     }