HTML API: Correct node name in generate_implied_end_tags().

The `generate_implied_end_tags()` algorithm has been comparing the
current node to a list of node names, which means that it won't ever
pop any elements from the stack of open elements.

This patch corrects the mistake by comparing node name against the
list, thus fixing the algorithm. This was noted in development work
for the 6.7 release.

Developed in WordPress#6988
Discussed in https://core.trac.wordpress.org/ticket/61576

Props dmsnell, jonsurrell.
See #61576.


git-svn-id: https://develop.svn.wordpress.org/trunk@58702 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/html-api/class-wp-html-processor.php

@@ -2771,7 +2771,7 @@ private function generate_implied_end_tags( $except_for_this_element = null ) {
 
 		while (
 			( $no_exclusions || ! $this->state->stack_of_open_elements->current_node_is( $except_for_this_element ) ) &&
-			in_array( $this->state->stack_of_open_elements->current_node(), $elements_with_implied_end_tags, true )
+			in_array( $this->state->stack_of_open_elements->current_node()->node_name, $elements_with_implied_end_tags, true )
 		) {
 			$this->state->stack_of_open_elements->pop();
 		}
@@ -2811,7 +2811,7 @@ private function generate_implied_end_tags_thoroughly() {
 			'TR',
 		);
 
-		while ( in_array( $this->state->stack_of_open_elements->current_node(), $elements_with_implied_end_tags, true ) ) {
+		while ( in_array( $this->state->stack_of_open_elements->current_node()->node_name, $elements_with_implied_end_tags, true ) ) {
 			$this->state->stack_of_open_elements->pop();
 		}
 	}