canvas: pop many clips on restore (#38496)

When restoring context/state we need to pop all clips from current
state, before we just poped one (even if there was none).

Testing: Added new WPT tests

---------

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

tests/wpt/meta/MANIFEST.json

@@ -480322,7 +480322,7 @@
         []
        ],
        "the-canvas-state.yaml": [
-        "230e45f80a5901cae395ed1c4c848556e333073d",
+        "c3f382ef92929aa86f26f5462a7bc6d0e8731854",
         []
        ],
        "the-canvas.yaml": [
@@ -711259,6 +711259,13 @@
          {}
         ]
        ],
+       "2d.state.saverestore.clip.2.html": [
+        "1f1372c2c34847a224434118d864b2431b054e01",
+        [
+         null,
+         {}
+        ]
+       ],
        "2d.state.saverestore.clip.html": [
         "b95a9a38c02740a4025850771c3bb8de5bb68403",
         [
@@ -725464,6 +725471,20 @@
          {}
         ]
        ],
+       "2d.state.saverestore.clip.2.html": [
+        "31805b52bc1ca2a0a3303762bf4d46e068a45e4d",
+        [
+         null,
+         {}
+        ]
+       ],
+       "2d.state.saverestore.clip.2.worker.js": [
+        "f3d49f9511a1c099795aa8fe93955881b761b2a9",
+        [
+         "html/canvas/offscreen/the-canvas-state/2d.state.saverestore.clip.2.worker.html",
+         {}
+        ]
+       ],
        "2d.state.saverestore.clip.html": [
         "08ddd216a8f90c9b4bf81ef04c8cf8829f6ef5e6",
         [