Update tests after merge.

src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IRaiseEventStatement.vb

@@ -291,14 +291,14 @@ IRaiseEventStatement (OperationKind.RaiseEventStatement) (Syntax: 'RaiseEvent  .
         IInstanceReferenceExpression (OperationKind.InstanceReferenceExpression, Type: TestClass, IsImplicit) (Syntax: 'TestEvent')
   Arguments(2):
       IArgument (ArgumentKind.Explicit, Matching Parameter: sender) (OperationKind.Argument) (Syntax: 'Nothing')
-        IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object, Constant: null) (Syntax: 'Nothing')
+        IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object, Constant: null, IsImplicit) (Syntax: 'Nothing')
           Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
           Operand: 
             ILiteralExpression (OperationKind.LiteralExpression, Type: null, Constant: null) (Syntax: 'Nothing')
         InConversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
         OutConversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
       IArgument (ArgumentKind.Explicit, Matching Parameter: e) (OperationKind.Argument) (Syntax: 'Nothing')
-        IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.EventArgs, Constant: null) (Syntax: 'Nothing')
+        IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.EventArgs, Constant: null, IsImplicit) (Syntax: 'Nothing')
           Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
           Operand: 
             ILiteralExpression (OperationKind.LiteralExpression, Type: null, Constant: null) (Syntax: 'Nothing')

src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IUsingStatement.vb

@@ -152,7 +152,7 @@ IUsingStatement (OperationKind.UsingStatement) (Syntax: 'Using c1 As ... End Usi
               null
             Arguments(1):
                 IArgument (ArgumentKind.Explicit, Matching Parameter: value) (OperationKind.Argument) (Syntax: 'c1')
-                  IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object) (Syntax: 'c1')
+                  IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object, IsImplicit) (Syntax: 'c1')
                     Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
                     Operand: 
                       ILocalReferenceExpression: c1 (OperationKind.LocalReferenceExpression, Type: Program.C) (Syntax: 'c1')

src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IVariableDeclaration.vb

@@ -657,7 +657,7 @@ IUsingStatement (OperationKind.UsingStatement) (Syntax: 'Using c1 As ... End Usi
               null
             Arguments(1):
                 IArgument (ArgumentKind.Explicit, Matching Parameter: value) (OperationKind.Argument) (Syntax: 'c1')
-                  IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object) (Syntax: 'c1')
+                  IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object, IsImplicit) (Syntax: 'c1')
                     Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
                     Operand: 
                       ILocalReferenceExpression: c1 (OperationKind.LocalReferenceExpression, Type: Program.C) (Syntax: 'c1')