CSS: Make the reliableTrDimensions support test work with Bootstrap CSS

Bootstrap 5 includes the following CSS on the page:

```css
*,
*::before,
*::after {
  box-sizing: border-box;
}
```

That threw our `reliableTrDimensions` support test off. This change fixes the
support test and adds a unit test ensuring support test values on a page
including Bootstrap 5 CSS are the same as on a page without it.

Fixes gh-5270
Closes gh-5278
Ref gh-5279

1 files changed, 2 insertions, 2 deletions

diff --git a/src/css/support.js b/src/css/support.js
index 48f95dc36..cf9f0cfcd 100644
--- a/src/css/support.js
+++ b/src/css/support.js
@@ -25,7 +25,7 @@ support.reliableTrDimensions = function() {
 		tr = document.createElement( "tr" );
 
 		table.style.cssText = "position:absolute;left:-11111px;border-collapse:separate";
-		tr.style.cssText = "border:1px solid";
+		tr.style.cssText = "box-sizing:content-box;border:1px solid";
 
 		// Support: Chrome 86+
 		// Height set through cssText does not get applied.
@@ -38,7 +38,7 @@ support.reliableTrDimensions = function() {
 		// display for all div elements is set to "inline",
 		// which causes a problem only in Android Chrome, but
 		// not consistently across all devices.
-		// Ensuring the div is display: block
+		// Ensuring the div is `display: block`
 		// gets around this issue.
 		div.style.display = "block";