[FlexNG] Remove float DCHECK

In CL:3508796, I had added a DCHECK to make sure an item wasn't an
OOF or a float (given that we were setting
|has_inflow_child_break_inside_line| when any flex item broke.)

However, it looks like for a display of -webkit-box,
IsFloatingOrOutOfFlowPositioned() with still be true for items that
specify a float value. Remove the DCHECK as a result.

Bug: 1318035
Change-Id: I8127cb068e3b8116ab05d6019cfb65d825d3c673
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3597086
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Alison Maher <almaher@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#994414}
diff --git a/css/css-break/flexbox/float-in-webkit-box-in-multicol-crash.html b/css/css-break/flexbox/float-in-webkit-box-in-multicol-crash.html
new file mode 100644
index 0000000..e939749
--- /dev/null
+++ b/css/css-break/flexbox/float-in-webkit-box-in-multicol-crash.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=1318035">
+<div style="column-count:2;">
+  <div style="display:-webkit-box;">
+    <div style="float:left;"></div>
+  </div>
+</div>