Remove redundant conditional.

src/Compilers/Core/Portable/Operations/ControlFlowGraphBuilder.cs

@@ -4679,8 +4679,7 @@ void checkLoopCondition()
                     }
                     else if (operation.StepValue.GetConstantValue() is { IsBad: false } value)
                     {
-                        if (value.Discriminator != ConstantValueTypeDiscriminator.Bad)
-                        {
+                        Debug.Assert(value.Discriminator != ConstantValueTypeDiscriminator.Bad);
                         if (value.IsNegativeNumeric)
                         {
                             comparisonKind = BinaryOperatorKind.GreaterThanOrEqual;
@@ -4690,7 +4689,6 @@ void checkLoopCondition()
                             comparisonKind = BinaryOperatorKind.LessThanOrEqual;
                         }
                     }
-                    }
 
                     // for signed integral steps not known at compile time
                     // we do    " (val Xor (step >> 31)) <= (limit Xor (step >> 31)) "