Remove now-fixed conformance errors.

conformance/failure_list_csharp.txt

-DurationProtoInputTooLarge.JsonOutput
-DurationProtoInputTooSmall.JsonOutput
-FieldMaskNumbersDontRoundTrip.JsonOutput
-FieldMaskPathsDontRoundTrip.JsonOutput
-FieldMaskTooManyUnderscore.JsonOutput
 JsonInput.AnyWithValueForInteger.JsonOutput
 JsonInput.AnyWithValueForJsonObject.JsonOutput
-JsonInput.BoolFieldAllCapitalFalse
-JsonInput.BoolFieldAllCapitalTrue
-JsonInput.BoolFieldCamelCaseFalse
-JsonInput.BoolFieldCamelCaseTrue
-JsonInput.BoolMapFieldKeyNotQuoted
-JsonInput.BytesFieldInvalidBase64Characters
-JsonInput.BytesFieldNoPadding
-JsonInput.DoubleFieldInfinityNotQuoted
-JsonInput.DoubleFieldNanNotQuoted
-JsonInput.DoubleFieldNegativeInfinityNotQuoted
-JsonInput.DoubleFieldTooLarge
-JsonInput.DoubleFieldTooSmall
-JsonInput.DurationHas3FractionalDigits.Validator
-JsonInput.DurationHas6FractionalDigits.Validator
-JsonInput.DurationHas9FractionalDigits.Validator
-JsonInput.DurationMaxValue.JsonOutput
-JsonInput.DurationMaxValue.ProtobufOutput
-JsonInput.DurationMinValue.JsonOutput
-JsonInput.DurationMinValue.ProtobufOutput
-JsonInput.EnumFieldNotQuoted
-JsonInput.EnumFieldNumericValueNonZero.JsonOutput
-JsonInput.EnumFieldNumericValueNonZero.ProtobufOutput
-JsonInput.EnumFieldNumericValueZero.JsonOutput
-JsonInput.EnumFieldNumericValueZero.ProtobufOutput
-JsonInput.EnumFieldUnknownValue.Validator
-JsonInput.FieldMaskInvalidCharacter
-JsonInput.FieldNameDuplicate
-JsonInput.FieldNameDuplicateDifferentCasing2
 JsonInput.FieldNameInLowerCamelCase.Validator
 JsonInput.FieldNameInSnakeCase.JsonOutput
 JsonInput.FieldNameInSnakeCase.ProtobufOutput
-JsonInput.FieldNameNotQuoted
 JsonInput.FieldNameWithMixedCases.JsonOutput
 JsonInput.FieldNameWithMixedCases.ProtobufOutput
 JsonInput.FieldNameWithMixedCases.Validator
-JsonInput.FloatFieldInfinityNotQuoted
-JsonInput.FloatFieldNanNotQuoted
-JsonInput.FloatFieldNegativeInfinityNotQuoted
-JsonInput.Int32FieldLeadingZero
 JsonInput.Int32FieldMinFloatValue.JsonOutput
 JsonInput.Int32FieldMinValue.JsonOutput
-JsonInput.Int32FieldNegativeWithLeadingZero
-JsonInput.Int32FieldPlusSign
-JsonInput.Int32MapFieldKeyNotQuoted
 JsonInput.Int64FieldMaxValueNotQuoted.JsonOutput
 JsonInput.Int64FieldMaxValueNotQuoted.ProtobufOutput
-JsonInput.Int64MapFieldKeyNotQuoted
-JsonInput.JsonWithComments
-JsonInput.MapFieldKeyIsNull
-JsonInput.MapFieldValueIsNull
-JsonInput.OneofFieldDuplicate
 JsonInput.OriginalProtoFieldName.JsonOutput
-JsonInput.OriginalProtoFieldName.ProtobufOutput
-JsonInput.RepeatedBoolWrapper.ProtobufOutput
-JsonInput.RepeatedDoubleWrapper.ProtobufOutput
-JsonInput.RepeatedFieldMessageElementIsNull
-JsonInput.RepeatedFieldPrimitiveElementIsNull
-JsonInput.RepeatedFieldTrailingComma
-JsonInput.RepeatedFloatWrapper.ProtobufOutput
-JsonInput.RepeatedInt32Wrapper.ProtobufOutput
-JsonInput.RepeatedInt64Wrapper.ProtobufOutput
-JsonInput.RepeatedUint32Wrapper.ProtobufOutput
-JsonInput.RepeatedUint64Wrapper.ProtobufOutput
-JsonInput.StringFieldInvalidEscape
-JsonInput.StringFieldSurrogateInWrongOrder
 JsonInput.StringFieldSurrogatePair.JsonOutput
-JsonInput.StringFieldUnpairedHighSurrogate
-JsonInput.StringFieldUnpairedLowSurrogate
-JsonInput.StringFieldUnterminatedEscape
-JsonInput.StringFieldUppercaseEscapeLetter
-JsonInput.TimestampHas3FractionalDigits.Validator
-JsonInput.TimestampHas6FractionalDigits.Validator
-JsonInput.TimestampHas9FractionalDigits.Validator
-JsonInput.TrailingCommaInAnObject
-JsonInput.Uint32MapFieldKeyNotQuoted
 JsonInput.Uint64FieldMaxValueNotQuoted.JsonOutput
 JsonInput.Uint64FieldMaxValueNotQuoted.ProtobufOutput
-JsonInput.Uint64MapFieldKeyNotQuoted
-JsonInput.ValueAcceptNull.JsonOutput
-JsonInput.ValueAcceptNull.ProtobufOutput
-TimestampProtoInputTooLarge.JsonOutput
-TimestampProtoInputTooSmall.JsonOutput