Auto merge of #14978 - shinglyu:inline-flex, r=notriddle

Implemented display: inline-flex

<!-- Please describe your changes on the following line: -->

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #14685 (github issue number if applicable).

<!-- Either: -->
- [x] There are tests for these changes
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/14978)
<!-- Reviewable:end -->

components/layout/inline.rs

@@ -1151,6 +1151,7 @@ impl InlineFlow {
             match (display_value, vertical_align_value) {
                 (display::T::inline, vertical_align::T::top) |
                 (display::T::block, vertical_align::T::top) |
+                (display::T::inline_flex, vertical_align::T::top) |
                 (display::T::inline_block, vertical_align::T::top) if
                         inline_metrics.space_above_baseline >= Au(0) => {
                     *largest_block_size_for_top_fragments = max(
@@ -1159,6 +1160,7 @@ impl InlineFlow {
                 }
                 (display::T::inline, vertical_align::T::bottom) |
                 (display::T::block, vertical_align::T::bottom) |
+                (display::T::inline_flex, vertical_align::T::bottom) |
                 (display::T::inline_block, vertical_align::T::bottom) if
                         inline_metrics.space_below_baseline >= Au(0) => {
                     *largest_block_size_for_bottom_fragments = max(