Replace exception-throwing with return value `Invalid` when unexpected value...

Replace exception-throwing with return value `Invalid` when unexpected value is encountered inIOperation APIs

src/Compilers/CSharp/Portable/BoundTree/Expression.cs

@@ -1123,7 +1123,7 @@ protected override OperationKind ExpressionKind
                         return OperationKind.BinaryOperatorExpression;
 
                     default:
-                        throw ExceptionUtilities.UnexpectedValue(this.OperatorKind & BinaryOperatorKind.OpMask);
+                        return OperationKind.InvalidExpression;
                 }
             }
         }

src/Compilers/VisualBasic/Portable/BoundTree/Expression.vb

@@ -774,7 +774,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                     Case BinaryOperatorKind.GreaterThan
                         Return BinaryOperationKind.OperatorMethodGreaterThan
                     Case Else
-                        Throw ExceptionUtilities.UnexpectedValue(OperatorKind And BinaryOperatorKind.OpMask)
+                        Return BinaryOperationKind.Invalid
                 End Select
             End Get
         End Property
@@ -808,7 +808,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                     Return OperationKind.BinaryOperatorExpression
             End Select
 
-            Throw ExceptionUtilities.UnexpectedValue(Me.OperatorKind And BinaryOperatorKind.OpMask)
+            Return OperationKind.InvalidExpression
         End Function
 
         Public Overrides Sub Accept(visitor As OperationVisitor)