Remove DHCECK within ComputeIntrinsicPadding.

This was added within:
https://chromium-review.googlesource.com/c/chromium/src/+/1754097

When we adjust the table-cell intrinsic-padding for scrollbars.
This calculation can safely ignore the block-start scrollbar if present.

Bug: 1008302
Change-Id: I3b747714da9c6736708b5b8d563450cdb13df524
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2136888Reviewed-by: Aleks Totic <atotic@chromium.org>
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756579}

third_party/blink/renderer/core/layout/ng/ng_length_utils.cc

@@ -804,7 +804,6 @@ NGBoxStrut ComputeIntrinsicPadding(const NGConstraintSpace& constraint_space,
                                    const ComputedStyle& style,
                                    const NGBoxStrut& scrollbar) {
   DCHECK(constraint_space.IsTableCell());
-  DCHECK(!scrollbar.block_start);
 
   // During the "layout" table phase, adjust the given intrinsic-padding to
   // accommodate the scrollbar.