[llvm] [SLP] NFC. Replace MainOp and AltOp in TreeEntry with InstructionsState. (PR #120198)

[Alexey Bataev via llvm-commits]

================
@@ -836,7 +836,7 @@ class InstructionsState {
     return getOpcode() == CheckedOpcode || getAltOpcode() == CheckedOpcode;
   }
 
-  InstructionsState() = delete;
+  InstructionsState() = default;
----------------
alexey-bataev wrote:

This is the change that should be avoided

https://github.com/llvm/llvm-project/pull/120198