[llvm] [AMDGPU] Reorganize tests to unblock #112403 (PR #115503)

[Shilei Tian via llvm-commits]

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@@ -1483,34 +1471,22 @@ define void @test_call_external_void_func_a15i32_inreg([15 x i32] inreg %arg0) #
 ; GFX11-NEXT:    s_mov_b32 s33, s0
 ; GFX11-NEXT:    s_waitcnt vmcnt(0)
 ; GFX11-NEXT:    s_setpc_b64 s[30:31]
-  call void @external_void_func_a15i32_inreg([15 x i32] inreg %arg0)
+  call void @external_void_func_a15i32_inreg([13 x i32] inreg %arg0)
   ret void
 }
 
-; FIXME:
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shiltian wrote:

These FIXME has been moved to the new file.

https://github.com/llvm/llvm-project/pull/115503