[llvm] [AMDGPU][NFC] Add test for 64-bit lshr with shifts >=32 (PR #138281)

[via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+;; Test reduction of:
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LU-JOHN wrote:

Files merged.

https://github.com/llvm/llvm-project/pull/138281