Update UIContainerLayouts.kt so graphics{} work better

[rafi0]

Fixes #2164

[soywiz]

Thanks! We will need to do the same for the rest, including UIHorizontalStack, etc.
Also we will need to add a test that verifies Y positions flor these views. And maybe a reference tests. Instead of texts, with solid rects that are less likely to fail due slight vector inconsistencies.

[soywiz]

Fixes #2164

[soywiz]

We need two things:

• Update UIHorizontalStack too.
• Add a test that checks the new behaviour.

My suggestion for the test is the following:

@Test
fun testUIVerticalStack() {
  val stack = UIVerticalStack()
  val view1 = stack.solidRect(10, 10, Colors.RED)
  val view2 = stack.graphics { fill(Colors.RED) { rect(10, 10, 20, 20) } }
  val view3 = stack.solidRect(10, 10, Colors.RED)
  stack.relayout()
  assertEquals("...", "${view1.y.niceStr},${view2.y.niceStr},${view3.y.niceStr}")
}

By applying/reverting this change the view3.y should be different. So that will cover that we have fixed the issue.

[soywiz]

LGTM

[soywiz]

Thank you very much!