wpt: Fix flakiness in vh_not_refreshing_on_chrome.html (#34626)

This test manually animates the height of an `<iframe>` that has content
which uses the `vh` unit. Each tick of the animation changes the height
by one pixel. Inside the `<iframe>` the element using `vh` units has a
transition applied, so every manual tick of the animation triggers a new
transition. The causes a pretty slow test execution.

This change improves `vh_not_refreshing_on_chrome.html` to remove
flakiness by making the test wait to start until after the `<iframe>` has
loaded and to increase the `<iframe>` height by 10 pixels instead of 1
when doing the manual animation. These changes make the test faster and
much less flaky in Servo.

In addition, the test is reformated a bit removing extraneous whitespace
and renamed to follow WPT naming conventions.

Fixes #23385.
Fixes #15570.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

tests/wpt/meta/MANIFEST.json

@@ -294185,6 +294185,21 @@
        {}
       ]
      ],
+     "vh-update-and-transition-in-subframe.html": [
+      "5e73ffc31153f0542de6fa4da37ef528d6866cd9",
+      [
+       null,
+       [
+        [
+         "/css/css-values/reference/vh-update-and-transition-in-subframe-ref.html",
+         "=="
+        ]
+       ],
+       {
+        "timeout": "long"
+       }
+      ]
+     ],
      "vh-zero-support.html": [
       "1c1bcd1761a2ffccfc1a92a10ddf860712606fa1",
       [
@@ -294198,21 +294213,6 @@
        {}
       ]
      ],
-     "vh_not_refreshing_on_chrome.html": [
-      "e5606a0cb751554602c2d108840300973e92c734",
-      [
-       null,
-       [
-        [
-         "/css/css-values/reference/vh_not_refreshing_on_chrome-ref.html",
-         "=="
-        ]
-       ],
-       {
-        "timeout": "long"
-       }
-      ]
-     ],
      "viewport-unit-011.html": [
       "055f3d1fd2d716a68d857738493815c8772bef06",
       [
@@ -440473,12 +440473,12 @@
        "cfa9e8d02d48436ee1c311da7c7bd65b0f4291cf",
        []
       ],
-      "vh_not_refreshing_on_chrome-ref.html": [
-       "279d1c69b9f7fbe60edb55b7e8a5d507eda24936",
+      "vh-update-and-transition-in-subframe-iframe-ref.html": [
+       "bc8216835883bc0314d76cb10f287f5202e3dc03",
        []
       ],
-      "vh_not_refreshing_on_chrome_iframe-ref.html": [
-       "5e35f6261e266be2981ae79038e464ac354cc8ef",
+      "vh-update-and-transition-in-subframe-ref.html": [
+       "ab068dfaf87773ebfaefbb3ab9d48f251760bc60",
        []
       ],
       "viewport-unit-011-ref.html": [
@@ -440740,10 +440740,6 @@
       "vh-support-transform-translate-iframe.html": [
        "f0b1b54c12d35da74bf19849612574a20339fe6a",
        []
-      ],
-      "vh_not_refreshing_on_chrome_iframe.html": [
-       "8d8e9b49d4aa3d9804a176852288e32ccaaa47d8",
-       []
       ]
      },
      "urls": {
@@ -440762,6 +440758,10 @@
        ]
       }
      },
+     "vh-update-and-transition-in-subframe-iframe.html": [
+      "61831f42f7d6ca1efe2e9534366f4b91da2ca155",
+      []
+     ],
      "viewport-units-001-print-ref.html": [
       "bc914522c7fcf556c69ba56d2d0ba792d7e92b89",
       []
@@ -474935,7 +474935,7 @@
     ]
    },
    "lint.ignore": [
-    "00fb7fd020192843abd6ba46baabd86ca0ce129f",
+    "4bf325500491b21f1556a365e14ebf1c96c9a516",
     []
    ],
    "loading": {