The set_position method computes the anchors/offsets to match a
rectangle at the given position with size "size_cache". However, when
the Control's combined minimum size is larger than the size obtained
through the offsets and anchors, "size_cache" is set to be as large as
the combined minimum size. Therefore, when position is set while the
combined minimum size is larger than the rectangle given by the anchors
and offsets, it would resize these two fields, which would then stop
the Control from shrinking when its combined minimum size decreased. To
fix this, set_position now uses the size given by the offsets and
anchors instead of the "size_cache" field. This way, the rectangle
denoted by the offsets and anchors is simply moved, without being
resized, enabling the Control to shrink automatically when its combined
minimum size decreases. I also added a test case to ensure that the
Control shrinks correctly after setting its position while it has a
larger custom minimum size than the one obtained through the offsets
and anchors.
