Remove a couple of asserts from display_list_unittest (flutter#173381)

Skia is updating some of the semantics around SkPath simple shape
inference [1]. Specifically, degenerate rounded rects are to be
reflected as simple rects instead of rrects.

The display list assertions should be sufficient for these tests.

This PR unblocks the Skia-side change.

[1] https://skia-review.googlesource.com/c/skia/+/1031900


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Author: fmalita

engine/src/flutter/display_list/display_list_unittests.cc

@@ -5251,7 +5251,6 @@ TEST_F(DisplayListTest, ClipRectRRectPathPromoteToClipRect) {
   DlRoundRect clip_rrect = DlRoundRect::MakeRect(clip_rect);
   DlRect draw_rect = clip_rect.Expand(2.0f, 2.0f);
   DlPath clip_path = DlPath::MakeRoundRect(clip_rrect);
-  ASSERT_TRUE(clip_path.IsRoundRect());
 
   DisplayListBuilder builder;
   builder.ClipPath(clip_path, DlClipOp::kIntersect, false);
@@ -5272,7 +5271,6 @@ TEST_F(DisplayListTest, ClipOvalRRectPathPromoteToClipOval) {
   DlRoundRect clip_rrect = DlRoundRect::MakeOval(clip_rect);
   DlRect draw_rect = clip_rect.Expand(2.0f, 2.0f);
   DlPath clip_path = DlPath::MakeRoundRect(clip_rrect);
-  ASSERT_TRUE(clip_path.IsRoundRect());
 
   DisplayListBuilder builder;
   builder.ClipPath(clip_path, DlClipOp::kIntersect, false);