[llvm] [llvm-reduce] Fix incorrectly ignored null MD in ReduceDIMetadata (PR #108541)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,50 @@
+; RUN: llvm-reduce %s -o %t --delta-passes=di-metadata --test FileCheck --test-arg %s --test-arg --input-file --abort-on-invalid-reduction
+; CHECK: , !dbg !11
+
+;; Tests for the bug fixed in PR#108541, where the presence of null metadata
+;; could result in a crash.
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
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arsenm wrote:

```suggestion
```
Shouldn't need these, shouldn't need to depend on x86 being built 

https://github.com/llvm/llvm-project/pull/108541