layout: Remove min and max container sizes from FlexContext (#35144)

Thanks to #34946 we don't have to recompute the min and max sizes, we
can get them from the `ContainingBlock`.

And then in `FlexContext` there is no need to store both the definite
and the min & max sizes of the container`, we can instead make do with
a single `FlexRelativeVec2<SizeConstraint>`.

This removes 1 of the 3 usages of `ContentBoxSizesAndPBMDeprecated`,
which is also good.

Signed-off-by: Oriol Brufau <obrufau@igalia.com>

components/layout_2020/formatting_contexts.rs

@@ -265,7 +265,6 @@ impl IndependentNonReplacedContents {
                 layout_context,
                 positioning_context,
                 containing_block_for_children,
-                containing_block,
             ),
             IndependentNonReplacedContents::Grid(fc) => fc.layout(
                 layout_context,