Reland Input type=text Shadow DOM With Performance Improvement (#37483)

Depends on #37427.

In addition to the changes introduced by
https://github.com/servo/servo/pull/37065, there are several performance
improvements and nits as follows:
- Use the internal pseudo element for style matching, this will reduce
the performance regression by ~66%.
- Manual construction of the `Text` node inside a text container. This
is followed by the modification of the inner `Text` node instead of
using `SetTextContent` which is more expensive.
- Use `implemented_pseudo_element` instead of
`text_control_inner_editor` `NodeFlag` to handle the special cases that
these elements should follow, specifically the:
  - focus delegation workaround;
  - selections; and
  - line height resolving.
- More documentation.

Servo's side of: https://github.com/servo/stylo/pull/217

Testing: No new unexpected WPT failure, except for the one introduced by
https://github.com/servo/servo/pull/37065/.
Fixes: #36307 #37205

---------

Signed-off-by: stevennovaryo <steven.novaryo@gmail.com>

components/layout/flow/inline/mod.rs

@@ -168,7 +168,8 @@ pub(crate) struct InlineFormattingContext {
     /// Whether or not this [`InlineFormattingContext`] contains floats.
     pub(super) contains_floats: bool,
 
-    /// Whether or not this is an [`InlineFormattingContext`] for a single line text input.
+    /// Whether or not this is an [`InlineFormattingContext`] for a single line text input's inner
+    /// text container.
     pub(super) is_single_line_text_input: bool,
 
     /// Whether or not this is an [`InlineFormattingContext`] has right-to-left content, which
@@ -2237,8 +2238,9 @@ fn line_height(
         LineHeight::Length(length) => length.0.into(),
     };
 
-    // Single line text inputs line height is clamped to the size of `normal`. See
-    // <https://github.com/whatwg/html/pull/5462>.
+    // The line height of a single-line text input's inner text container is clamped to
+    // the size of `normal`.
+    // <https://html.spec.whatwg.org/multipage/#the-input-element-as-a-text-entry-widget>
     if is_single_line_text_input {
         line_height.max_assign(font_metrics.line_gap);
     }