[llvm] [DAGCombiner] Fix check for extending loads (PR #112182)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,29 @@
+; RUN: llc -mtriple=aarch64-unknown-linux-gnu < %s | FileCheck %s
+
----------------
arsenm wrote:

Can you merge this test with whatever test was added in the original combine? 

https://github.com/llvm/llvm-project/pull/112182