Created Issue: [0.2.x] typeBuilder does not generate end padding for structures [12592]

```
#prama pack (4)
struct str1 {
long field1;
char field2;
};

C_ASSERT( sizeof(str1) == 8 )
```
```
tb = pykd.typeBuilder()
struct = tb.createStruct(name ="MyAlignStruct", align=4)
struct.append( "field1", tb.UInt4B )
struct.append( "field2", tb.UInt1B )
print "size = ", struct.size(), "filed2 offset =", struct.fieldOffset("field2")
```
Expected: size = 8, filed2 offset = 4
Actual: size = 5, m_filed2 offset = 4