[NUI][TCSACR-324][Remove Tizen.NUI.BaseComponents.FlexContainer testcases]

[NUI][TCSACR-324][Remove Tizen.NUI.BaseComponents.FlexContainer testcases]

- FlexContainer class is deprecated in TCSACR-324.
 : FlexContainer()
   FlexContainer.Alignment AlignContent { get; set; }
   FlexContainer.Alignment AlignItems { get; set; }
   FlexContainer.ContentDirectionType ContentDirection { get; set; }
   FlexContainer.FlexDirectionType FlexDirection { get; set; }
   FlexContainer.Justification JustifyContent { get; set; }
   FlexContainer.WrapType FlexWrap { get; set; }
   FlexContainer.Alignment
    AlignAuto = 0
    AlignFlexStart = 1
    AlignCenter = 2
    AlignFlexEnd = 3
    AlignStretch = 4
   FlexContainer.ContentDirectionType
    Inherit = 0
    LTR = 1
    RTL = 2
   FlexContainer.FlexDirectionType
    Column = 0
    ColumnReverse = 1
    Row = 2
    RowReverse = 3
   FlexContainer.Justification
    JustifyFlexStart = 0
    JustifyCenter = 1
    JustifyFlexEnd = 2
    JustifySpaceBetween = 3
    JustifySpaceAround = 4
   FlexContainer.WrapType
    NoWrap = 0
    Wrap = 1
   float Flex { get; set; }
   int AlignSelf { get; set; }
   Tizen.NUI.Vector4 FlexMargin { get; set; }

Change-Id: I10e1a363997e6bc35a38a1f92d2704026ed023ce
Signed-off-by: Seoyeon Kim <seoyeon2.kim@samsung.com>