WebKit export of https://bugs.webkit.org/show_bug.cgi?id=243300 (#35265)

diff --git a/css/css-contain/contain-size-button-001.html b/css/css-contain/contain-size-button-001.html
index 4b2ecd7..9048352 100644
--- a/css/css-contain/contain-size-button-001.html
+++ b/css/css-contain/contain-size-button-001.html
@@ -9,6 +9,7 @@
 button {
   border: 5px solid green;
   padding: 0;
+  margin: 0;
   contain: size;
   color: transparent;
   font-size: 2em;
diff --git a/css/css-contain/contain-size-button-002-ref.html b/css/css-contain/contain-size-button-002-ref.html
index efadf9b..6cf0e4a 100644
--- a/css/css-contain/contain-size-button-002-ref.html
+++ b/css/css-contain/contain-size-button-002-ref.html
@@ -7,6 +7,7 @@
   <style>
   button {
     border: 1em solid green;
+    margin: 0;
     /* In case the testcase's 'inner' text is taller than the button, don't let
        it influence its line-box's size.  This lets us more-easily compare
        sizing between empty buttons vs. contained nonempty buttons. */
diff --git a/css/css-contain/contain-size-button-002.html b/css/css-contain/contain-size-button-002.html
index 9a2df76..d6b6d0d 100644
--- a/css/css-contain/contain-size-button-002.html
+++ b/css/css-contain/contain-size-button-002.html
@@ -9,6 +9,7 @@
   <style>
   button {
     contain: size;
+    margin: 0;
     border: 1em solid green;
     /* In case the testcase's 'inner' text is taller than the button, don't let
        it influence its line-box's size.  This lets us more-easily compare