[LV] Remove unused requiresScalarEpilogue function. nfc (#135341)

Author: Mel-Chen

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -1373,21 +1373,6 @@ class LoopVectorizationCostModel {
     return false;
   }
 
-  /// Returns true if we're required to use a scalar epilogue for at least
-  /// the final iteration of the original loop for all VFs in \p Range.
-  /// A scalar epilogue must either be required for all VFs in \p Range or for
-  /// none.
-  bool requiresScalarEpilogue(VFRange Range) const {
-    auto RequiresScalarEpilogue = [this](ElementCount VF) {
-      return requiresScalarEpilogue(VF.isVector());
-    };
-    bool IsRequired = all_of(Range, RequiresScalarEpilogue);
-    assert(
-        (IsRequired || none_of(Range, RequiresScalarEpilogue)) &&
-        "all VFs in range must agree on whether a scalar epilogue is required");
-    return IsRequired;
-  }
-
   /// Returns true if a scalar epilogue is not allowed due to optsize or a
   /// loop hint annotation.
   bool isScalarEpilogueAllowed() const {